msm: pm2: Add CPR specific function callbacks to PM driver

CPR(Core Power Reduction) is a new h/w block added in 8x25
2.0 revision. This block reduce the power consumption of
SOC using sensors inside the SOC. Add function callbacks to
PM driver to perform disable, enable, save and restore of
CPR context data when the core do an IdlePC.

Change-Id: I4f9ba9a06919c58c6fe2cbc8ce60267be5ce7f22
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>