Add pin initializiation for KBD75 (#5129)

So that the LED indicator actually works

keyboards/kbdfans/kbd75/rev1/rev1.c

@@ -10,3 +10,8 @@ void led_set_kb(uint8_t usb_led) {
 
 	led_set_user(usb_led);
 }
+
+void matrix_init_kb(void) {
+  setPinOutput(B2);
+  matrix_init_user();
+}

keyboards/kbdfans/kbd75/rev2/rev2.c

@@ -10,3 +10,8 @@ void led_set_kb(uint8_t usb_led) {
 
 	led_set_user(usb_led);
 }
+
+void matrix_init_kb(void) {
+  setPinOutput(B2);
+  matrix_init_user();
+}