ARM: dts: msm: add pinctrl support in mdss for msm8916

Add pinctrl support for the installation
of the required GPIOs from DT. Modify msm8916 board
device tree.

Change-Id: I1576f4fd63bca046c199843c7fb14f5715b4c1b2
Signed-off-by: Manoj Rao <manojraj@codeaurora.org>
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>