Move SPLIT_KEYBOARD to data driven (#21410)

keyboards/rgbkb/mun/info.json

@@ -0,0 +1,5 @@
+{
+    "split": {
+        "enabled": true
+    }
+}

keyboards/rgbkb/mun/rules.mk

@@ -22,7 +22,6 @@ OLED_ENABLE = yes
 
 ENCODER_ENABLE = yes
 
-SPLIT_KEYBOARD = yes
 SERIAL_DRIVER = usart
 LTO_ENABLE = yes
 OPT = 3

keyboards/rgbkb/sol/info.json

@@ -0,0 +1,5 @@
+{
+    "split": {
+        "enabled": true
+    }
+}

keyboards/rgbkb/sol/rules.mk

@@ -1,7 +1,6 @@
 # Custom local font file
 OPT_DEFS += -DOLED_FONT_H=\"common/glcdfont.c\"
 
-SPLIT_KEYBOARD = yes
 ENCODER_ENABLE = yes
 
 DEFAULT_FOLDER = rgbkb/sol/rev2

keyboards/rgbkb/sol3/info.json

@@ -0,0 +1,5 @@
+{
+    "split": {
+        "enabled": true
+    }
+}

keyboards/rgbkb/sol3/rules.mk

@@ -26,7 +26,6 @@ OLED_ENABLE = yes
 
 ENCODER_ENABLE = yes
 
-SPLIT_KEYBOARD = yes
 SERIAL_DRIVER = usart
 LTO_ENABLE = yes
 OPT = 3

keyboards/rgbkb/zen/info.json

@@ -0,0 +1,5 @@
+{
+    "split": {
+        "enabled": true
+    }
+}

keyboards/rgbkb/zen/rules.mk

@@ -8,7 +8,6 @@ CONSOLE_ENABLE = no         # Console for debug
 COMMAND_ENABLE = yes        # Commands for debug and configuration
 NKRO_ENABLE = no            # Enable N-Key Rollover
 AUDIO_ENABLE = no           # Audio output
-SPLIT_KEYBOARD = yes
 RGBLIGHT_ENABLE = yes       # Enable WS2812 RGB underlight
 
 DEFAULT_FOLDER = rgbkb/zen/rev2

keyboards/rgbkb/zygomorph/info.json

@@ -0,0 +1,5 @@
+{
+    "split": {
+        "enabled": true
+    }
+}

keyboards/rgbkb/zygomorph/rules.mk

@@ -11,8 +11,6 @@ BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
 RGBLIGHT_ENABLE = yes       # Enable keyboard RGB underglow
 AUDIO_ENABLE = no           # Audio output
 
-SPLIT_KEYBOARD = yes
-
 DEFAULT_FOLDER = rgbkb/zygomorph/rev1
 
 # Disable unsupported hardware