backlight: lm3630a_bl: Simplify probe return on gpio request error

Code can be simpler: return directly when devm_gpiod_get_optional()
failed.

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240305-backlight-probe-v2-6-609b0cf24bde@linaro.org


Signed-off-by: Lee Jones <lee@kernel.org>