msm: rpm_stats: Add support to read master PC stats from RPM MSG RAM.

RPM maintains PC stats for each master in MSG RAM and it allocates
256 bytes for this use. No of masters differs for different targets.

Initialize the resources for rpm_master_stat platform device.

Signed-off-by: Anji Jonnala <anjir@codeaurora.org>

Change-Id: I0a44b083fd01a852ba214ecf1d2e6d953c154ed5
Signed-off-by: Neha Pandey <nehap@codeaurora.org>