On Sunrise Point PCH, the Power Management Controller provides 4K bytes of
memory space for various power management and debug registers. This fix is
needed to access power management & debug registers that are mapped at a
higher offset.

Also, this provides a fix for correctly masking the PWRMBASE as the initial
bits (0-11) are reserved.
Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>