vc/amd/fsp: Add Morgana FSP vendorcode

vc/amd/fsp: Add Morgana FSP vendorcode

Initial commit of the FSP-specific code for the Morgana SoC.

This is just an initial framework and still needs to be updated
to match the Morgana FSP.

Signed-off-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Change-Id: Ic53c59404f96c73c55eb2648113c5ced26d6e20c
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68192
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>