refactor SPLIT_KEYBOARD, OLED_DRIVER_ENABLE (#10405)

keyboards/claw44/rules.mk

@@ -22,7 +22,6 @@ CONSOLE_ENABLE = no         # Console for debug
 COMMAND_ENABLE = no        # Commands for debug and configuration
 NKRO_ENABLE = no            # Nkey Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
 BACKLIGHT_ENABLE = no      # Enable keyboard backlight functionality
-MIDI_ENABLE = no            # MIDI controls
 AUDIO_ENABLE = no           # Audio output on port C6
 UNICODE_ENABLE = no         # Unicode
 BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
@@ -30,12 +29,4 @@ RGBLIGHT_ENABLE = no       # Enable WS2812 RGB underlight.
 # Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
 SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
 
-CUSTOM_MATRIX = yes
-SRC += i2c.c
-SRC += serial.c
-SRC += ssd1306.c
-
-# if firmware size over limit, try this option
-# CFLAGS += -flto
-
 DEFAULT_FOLDER = claw44/rev1