msm: 8960: Add support for PASR in DMM.

8960 v2 and future devices only support PASR, so the RPM interface
for DMM should trigger self-refresh instead of deep power down.

Add support to provide a logical grouping of memory regions
that abstract the physical memory topology to achieve independent
power control. The mode of power control is automatically switched
based on the version of the device.

Change-Id: I93fddc9437ba2eaffbb2853f9d91dadb2edc5d0b
Signed-off-by: Naveen Ramaraj <nramaraj@codeaurora.org>