ARM: dts: msm: optimize time of backlight up on spyro

Enable backlight control in order to optimize time of
backlight up when exit idle mode on spyro wdp.

Change-Id: Ia7811d0cf8338a785ff27c5859b963c0a277919c
Signed-off-by: Xipeng Gu <guxipeng@codeaurora.org>