soc/intel/common/block: Add Intel common PCR support

soc/intel/common/block: Add Intel common PCR support

IOSF_SB message space is used to access registers mapped
on IOSF-SB. These registers include uncore CRs (configuration
registers) and chipset specific registers. The Private
Configuration Register (PCR) space is accessed on IOSF-SB
using destination ID also known as Port ID.

Access to IOSF-SB by the Host or System Agent is possible
over PSF via the Primary to Sideband Bridge (P2SB). P2SB will
forward properly formatted register access requests as CRRd and
CRWr request via IOSF-SB.

Change-Id: I78526a86b6d10f226570c08050327557e0bb2c78
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/18669
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>