Add support for RGB LEDs wired directly to each half's controller (#5392)

* Add support for wiring RGB LEDs for both halves directly to their respective controllers

RGB LEDs for each half don't need to be chained together across the TRRS cable with this

* Add split RGB LED support for serial

* Update config/rules for bakingpy layout

* Un-nest ifdefs for hand detection

* Read RGB config state from memory instead of EEPROM for serial updates

* Reuse existing LED pointer instead of creating new one

keyboards/keebio/iris/rev3/config.h

@@ -71,6 +71,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* ws2812 RGB LED */
 #define RGB_DI_PIN F7
 #define RGBLED_NUM 12    // Number of LEDs
+#define RGBLED_SPLIT { 6, 6 }
 
 #define DYNAMIC_KEYMAP_LAYER_COUNT 4