ARM: dts: msm: Make L2 the master for voltage control on APQ8084

APQ8084 uses a single gang to power the krait PDN. The comminications
to the PMIC to change voltage and the phases are done via L2's PVC port.
Set the flag to enable it.

Change-Id: I6c9b32a351586db2aa271c4318765d989468f271
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>