ARM: dts: msm: Add battery FET regulator to mdp device

Add usage of battery FET(batfet) regulator to control batfet going into
HPM/LPM modes.

Change-Id: Iaab2261905e560dc6cbd7ad028574f86961a3045
CRs-Fixed: 550440
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>
Signed-off-by: Shalabh Jain <shalabhj@codeaurora.org>