platform/chrome: cros_kbd_led_backlight: Remove OF match

After applying 4c03a44e ("arm64: dts: mediatek: mt8195-cherry: Remove
keyboard-backlight node"), there are no users for using the OF match.
Instead, the device is added via drivers/mfd/cros_ec_dev.c by
970c3a6b ("mfd: cros_ec: Register keyboard backlight subdevice").

Remove the OF match.

Link: https://lore.kernel.org/r/20241206031405.1711996-2-tzungbi@kernel.org


Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>