MIPS: ip30: ip30-console: Add missing include

commit 8de4ed75bd14ed197119ac509c6902a8561e0c1c upstream.

Include linux/processor.h to fix build error:

arch/mips/sgi-ip30/ip30-console.c: In function ‘prom_putchar’:
arch/mips/sgi-ip30/ip30-console.c:21:17: error: implicit declaration of function ‘cpu_relax’ [-Werror=implicit-function-declaration]
   21 |                 cpu_relax();

Cc: [email protected]
Signed-off-by: Jiaxun Yang <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
(cherry picked from commit 97f099862aa4c865056046fce4e1b8ab2f18bd43)

arch/mips/sgi-ip30/ip30-console.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #include <linux/io.h>
+#include <linux/processor.h>
 
 #include <asm/sn/ioc3.h>