arm64: dts: mediatek: mt8195-cherry: Remove keyboard-backlight node

arm64: dts: mediatek: mt8195-cherry: Remove keyboard-backlight node

Commit 970c3a6b7aa3 ("mfd: cros_ec: Register keyboard backlight
subdevice") introduced support for detecting keyboard backlight
fuctionality through communication with the ChromeOS EC. This means that
the DT node is no longer used. Remove the unneeded node.

Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20240722-cros-backlight-dt-probe-v2-1-d77cdf7018ec@collabora.com
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>