Fix comment banner descriptions of p384_montjscalarmul argument sizes

As pointed out by June Lee in the code review, the various forms of
the new function p384_montjscalarmul[_alt] all had the same typo in
the comment banner of the code, where the Jacobian points were shown
as size 12 instead of 3*6 = 18. The actual C header files in
include/s2n-bignum*.h were already correct.

arm/p384/p384_montjscalarmul.S

@@ -3,12 +3,12 @@
 
 // ----------------------------------------------------------------------------
 // Montgomery-Jacobian form scalar multiplication for P-384
-// Input scalar[6], point[12]; output res[12]
+// Input scalar[6], point[18]; output res[18]
 //
 // extern void p384_montjscalarmul
-//   (uint64_t res[static 12],
+//   (uint64_t res[static 18],
 //    uint64_t scalar[static 6],
-//    uint64_t point[static 12]);
+//    uint64_t point[static 18]);
 //
 // This function is a variant of its affine point version p384_scalarmul.
 // Here, input and output points are assumed to be in Jacobian form with

arm/p384/p384_montjscalarmul_alt.S

@@ -3,12 +3,12 @@
 
 // ----------------------------------------------------------------------------
 // Montgomery-Jacobian form scalar multiplication for P-384
-// Input scalar[6], point[12]; output res[12]
+// Input scalar[6], point[18]; output res[18]
 //
 // extern void p384_montjscalarmul_alt
-//   (uint64_t res[static 12],
+//   (uint64_t res[static 18],
 //    uint64_t scalar[static 6],
-//    uint64_t point[static 12]);
+//    uint64_t point[static 18]);
 //
 // This function is a variant of its affine point version p384_scalarmul_alt.
 // Here, input and output points are assumed to be in Jacobian form with

x86/p384/p384_montjscalarmul.S

@@ -3,12 +3,12 @@
 
 // ----------------------------------------------------------------------------
 // Montgomery-Jacobian form scalar multiplication for P-384
-// Input scalar[6], point[12]; output res[12]
+// Input scalar[6], point[18]; output res[18]
 //
 // extern void p384_montjscalarmul
-//   (uint64_t res[static 12],
+//   (uint64_t res[static 18],
 //    uint64_t scalar[static 6],
-//    uint64_t point[static 12]);
+//    uint64_t point[static 18]);
 //
 // This function is a variant of its affine point version p384_scalarmul.
 // Here, input and output points are assumed to be in Jacobian form with

x86/p384/p384_montjscalarmul_alt.S

@@ -3,12 +3,12 @@
 
 // ----------------------------------------------------------------------------
 // Montgomery-Jacobian form scalar multiplication for P-384
-// Input scalar[6], point[12]; output res[12]
+// Input scalar[6], point[18]; output res[18]
 //
 // extern void p384_montjscalarmul_alt
-//   (uint64_t res[static 12],
+//   (uint64_t res[static 18],
 //    uint64_t scalar[static 6],
-//    uint64_t point[static 12]);
+//    uint64_t point[static 18]);
 //
 // This function is a variant of its affine point version p384_scalarmul.
 // Here, input and output points are assumed to be in Jacobian form with

x86_att/p384/p384_montjscalarmul.S

@@ -3,12 +3,12 @@
 
 // ----------------------------------------------------------------------------
 // Montgomery-Jacobian form scalar multiplication for P-384
-// Input scalar[6], point[12]; output res[12]
+// Input scalar[6], point[18]; output res[18]
 //
 // extern void p384_montjscalarmul
-//   (uint64_t res[static 12],
+//   (uint64_t res[static 18],
 //    uint64_t scalar[static 6],
-//    uint64_t point[static 12]);
+//    uint64_t point[static 18]);
 //
 // This function is a variant of its affine point version p384_scalarmul.
 // Here, input and output points are assumed to be in Jacobian form with

x86_att/p384/p384_montjscalarmul_alt.S

@@ -3,12 +3,12 @@
 
 // ----------------------------------------------------------------------------
 // Montgomery-Jacobian form scalar multiplication for P-384
-// Input scalar[6], point[12]; output res[12]
+// Input scalar[6], point[18]; output res[18]
 //
 // extern void p384_montjscalarmul_alt
-//   (uint64_t res[static 12],
+//   (uint64_t res[static 18],
 //    uint64_t scalar[static 6],
-//    uint64_t point[static 12]);
+//    uint64_t point[static 18]);
 //
 // This function is a variant of its affine point version p384_scalarmul.
 // Here, input and output points are assumed to be in Jacobian form with