backlight: lms501kf03: Remove unused const variables

W=1 kernel build reports:

 drivers/video/backlight/lms501kf03.c:96:28: warning: ‘seq_sleep_in’ defined but not used [-Wunused-const-variable=]
 96 | static const unsigned char seq_sleep_in[] = {
 | ^~~~~~~~~~~~
 drivers/video/backlight/lms501kf03.c:92:28: warning: ‘seq_up_dn’ defined but not used [-Wunused-const-variable=]
 92 | static const unsigned char seq_up_dn[] = {
 | ^~~~~~~~~

Either 'seq_sleep_in' nor 'seq_up_dn' have been used since the
driver first landed in 2013.

Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>