mb/intel/mtlrvp: Add MTL reference mainboard for MTLRVP-P

mb/intel/mtlrvp: Add MTL reference mainboard for MTLRVP-P

This adds an initial mainboard code for mtlrvp, Intel Meteorlake
reference platform.

BUG=b:224325352
TEST=util/abuild/abuild -p none -t intel/mtlrvp -a -c max

Signed-off-by: Jamie Ryu <jamie.m.ryu@intel.com>
Signed-off-by: Usha P <usha.p@intel.com>
Change-Id: I097db4de9734ff81283cf470aabf3eb23b63aab8
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66097
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Balaji Manigandan <balaji.manigandan@intel.com>
Reviewed-by: Sridhar Siricilla <sridhar.siricilla@intel.com>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>