msm: 8226: Add lcd enable gpiomux config

Certain display panels on msm8226 require an enable gpio
as part of their power up sequence. Add the gpiomux
configuration for this enable gpio.

Change-Id: I5a00d66c914d56f9856596c3bcd45d436263f3e0
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>