Add RGB Matrix support for Preonic rev3 (#12008)

* Add g_led_config for RGB Matrix support

* Corrected indentation

* Undo indentation on existing rev3.c code

Co-authored-by: filterpaper <filterpaper@localhost>

keyboards/preonic/rev3/rules.mk

@@ -25,6 +25,10 @@ API_SYSEX_ENABLE = no
 SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
 #SLEEP_LED_ENABLE = yes
 
+# Do not enable RGB_MATRIX_ENABLE together with RGBLIGHT_ENABLE
+RGB_MATRIX_ENABLE = no
+RGB_MATRIX_DRIVER = WS2812
+
 # SERIAL_LINK_ENABLE = yes
 ENCODER_ENABLE = yes
 DIP_SWITCH_ENABLE = yes