arm: Select PM_OPP on MSM architectures

The Operating Power Point library provides a framework
for the storage and communication of frequency-to-voltage
tables between drivers and modules. Select it on MSM
architectures.

Change-Id: Ifed6280745ceb7a380946899269b3ef8f6330b63
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>