ARM: dts: msm: Add MPP and GPIO config for msm8939 CDP/MTP

Add the required MPP/GPIO configuration for PM8916 on
8939. Configure MPP4 for PWM back-light and GPIO 2 for
NFC clock control.

Change-Id: Id9cd041c39cd5463ac84f29bbe636e372fb345f6
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>