backlight: lp855x: Drop ret variable in brightness change function

Fixes the following warning:

drivers/video/backlight/lp855x_bl.c:252:7: warning: variable 'ret' is used
uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]

Signed-off-by: Artur Weber <aweber.kernel@gmail.com>
Fixes: 5145531b ("backlight: lp855x: Catch errors when changing brightness")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308091728.NEJhgUPP-lkp@intel.com/


Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20230809114216.4078-1-aweber.kernel@gmail.com


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