msm: board-8930: Add backlight control when using PM8917

Use PM8917 GPIO 24 to enable and disable the LCD backlight on
targets which use PM8917 as WLED is not available.

Change-Id: Id2fa1bb01d174d38ee9d846261750e971a96cfd2
Signed-off-by: David Collins <collinsd@codeaurora.org>
2 files changed