Add support for 4 IS31FL3731 devices (#10860)

This is a simple change.Support for IS31FL3731 has been changed from 2 to 4.

quantum/rgb_matrix_drivers.c

@@ -34,6 +34,12 @@ static void init(void) {
 #        ifdef DRIVER_ADDR_2
     IS31FL3731_init(DRIVER_ADDR_2);
 #        endif
+#        ifdef DRIVER_ADDR_3
+    IS31FL3731_init(DRIVER_ADDR_3);
+#        endif
+#        ifdef DRIVER_ADDR_4
+    IS31FL3731_init(DRIVER_ADDR_4);
+#        endif
 #    elif defined(IS31FL3733)
     IS31FL3733_init(DRIVER_ADDR_1, 0);
 #    elif defined(IS31FL3737)
@@ -60,6 +66,12 @@ static void init(void) {
 #        ifdef DRIVER_ADDR_2
     IS31FL3731_update_led_control_registers(DRIVER_ADDR_2, 1);
 #        endif
+#        ifdef DRIVER_ADDR_3
+    IS31FL3731_update_led_control_registers(DRIVER_ADDR_3, 2);
+#        endif
+#        ifdef DRIVER_ADDR_4
+    IS31FL3731_update_led_control_registers(DRIVER_ADDR_4, 3);
+#        endif
 #    elif defined(IS31FL3733)
     IS31FL3733_update_led_control_registers(DRIVER_ADDR_1, 0);
     IS31FL3733_update_led_control_registers(DRIVER_ADDR_2, 1);
@@ -76,6 +88,12 @@ static void flush(void) {
 #        ifdef DRIVER_ADDR_2
     IS31FL3731_update_pwm_buffers(DRIVER_ADDR_2, 1);
 #        endif
+#        ifdef DRIVER_ADDR_3
+    IS31FL3731_update_pwm_buffers(DRIVER_ADDR_3, 2);
+#        endif
+#        ifdef DRIVER_ADDR_4
+    IS31FL3731_update_pwm_buffers(DRIVER_ADDR_4, 3);
+#        endif
 }
 
 const rgb_matrix_driver_t rgb_matrix_driver = {