platform/x86: intel_pmc_core: Make the driver PCH family agnostic

Although this driver did pretty good job in abstracting PCH specific
interfaces, but still there are some loose ends. For example
SLP_S0 counter (for reading SLP_S0 residency), PM config offset (for
checking permissions to read XRAM) and PPFEAR offset (for reading IP
status) is still hardcoded for a specific family of PCH.

This change extended the struct pmc_reg_map to allow per family
configuration of offsets and bits.

No functional change is expected with this change. This change allows
seamless additions to new PCH and create a baseline for other platform
specific extensions.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>