leds: qcom-lpg: Check the return value of regmap_bulk_write()

leds: qcom-lpg: Check the return value of regmap_bulk_write()

The lpg_lut_store() function currently ignores the return value of
regmap_bulk_write() and always returns 0. This can cause hardware write
failures to go undetected, leading the caller to believe LUT programming
succeeded when it may have failed.

Check the return value of regmap_bulk_write() in lpg_lut_store and return
the error to the caller on failure.

Fixes: 24e2d05d1b68 ("leds: Add driver for Qualcomm LPG")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Link: https://patch.msgid.link/20260108175133.638-1-vulab@iscas.ac.cn
Signed-off-by: Lee Jones <lee@kernel.org>