OMAP4: powerdomains: add PRCM partition data; use OMAP4 PRM functions
OMAP4 powerdomain control registers are split between the PRM hardware
module and the PRCM_MPU local PRCM. Add this PRCM partition
information to each OMAP4 powerdomain record, and convert the OMAP4
powerdomain function implementations to use the OMAP4 PRM instance
functions.
Also fixes a potential null pointer dereference of pwrdm->name.