drivers/video/backlight: rename da903x to da903x_bl

Currently both da903x backlight and voltage reulator drivers have the
same name. Rename the backlight driver to allow use of both drivers as
modules.

Signed-off-by: Mike Rapoport <[e-mail]>
Acked-by: Eric Miao <[e-mail]>
Cc: Richard Purdie <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/video/backlight/Makefile

···
 obj-$(CONFIG_BACKLIGHT_PROGEAR) += progear_bl.o
 obj-$(CONFIG_BACKLIGHT_CARILLO_RANCH) += cr_bllcd.o
 obj-$(CONFIG_BACKLIGHT_PWM)	+= pwm_bl.o
-obj-$(CONFIG_BACKLIGHT_DA903X)	+= da903x.o
+obj-$(CONFIG_BACKLIGHT_DA903X)	+= da903x_bl.o
 obj-$(CONFIG_BACKLIGHT_MBP_NVIDIA) += mbp_nvidia_bl.o
 obj-$(CONFIG_BACKLIGHT_TOSA)	+= tosa_bl.o
 obj-$(CONFIG_BACKLIGHT_SAHARA)	+= kb3886_bl.o