is31fl3741: Allow changing config register (qmk#21861)

When not all SW pins are used, it's useful to disable those that aren't.
Can reduce audible noise.

```
Layout:
D7:D4 D3  D2:D1 D0
SWD   LGC OSDE  SSD

SWS: SWx Setting. Change how many SW pins are active
LGC: H/L Logic
SSD: Software Shutdown Control
```

Signed-off-by: Daniel Schaefer <[email protected]>

Author: JohnAZoidberg

drivers/led/issi/is31fl3741.c

@@ -61,6 +61,10 @@
 #    define ISSI_PERSISTENCE 0
 #endif
 
+#ifndef ISSI_CONFIGURATION
+#    define ISSI_CONFIGURATION 0x01
+#endif
+
 #ifndef ISSI_SWPULLUP
 #    define ISSI_SWPULLUP PUR_32KR
 #endif
@@ -162,7 +166,7 @@ void is31fl3741_init(uint8_t addr) {
     is31fl3741_write_register(addr, ISSI_COMMANDREGISTER, ISSI_PAGE_FUNCTION);
 
     // Set to Normal operation
-    is31fl3741_write_register(addr, ISSI_REG_CONFIGURATION, 0x01);
+    is31fl3741_write_register(addr, ISSI_REG_CONFIGURATION, ISSI_CONFIGURATION);
 
     // Set Golbal Current Control Register
     is31fl3741_write_register(addr, ISSI_REG_GLOBALCURRENT, ISSI_GLOBALCURRENT);