drivers/built-in.o: In function `aat2870_bl_remove':
aat2870_bl.c:(.text+0x414f9): undefined reference to `backlight_device_unregister'
drivers/built-in.o: In function `aat2870_bl_probe':
aat2870_bl.c:(.text+0x418fc): undefined reference to `backlight_device_register'
aat2870_bl.c:(.text+0x41a31): undefined reference to `backlight_device_unregiste
Cc: Jin Park <jinyoungp@nvidia.com> Cc: Samuel Ortiz <sameo@linux.intel.com> Cc: Axel Lin <axel.lin@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>