mb/intel/mtlrvp: Include fw_config.c file

Update Makefile to include fw_config file for mtlrvp board.

Signed-off-by: Anil Kumar <anil.kumar.k@intel.com>
Change-Id: Id41cd8b015a796f7a959ceccf85106a48d15ae35
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82559
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Bora Guvendik <bora.guvendik@intel.com>
Reviewed-by: Jamie Ryu <jamie.m.ryu@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/intel/mtlrvp/Makefile.mk b/src/mainboard/intel/mtlrvp/Makefile.mk
index d8144c8..6c93add 100644
--- a/src/mainboard/intel/mtlrvp/Makefile.mk
+++ b/src/mainboard/intel/mtlrvp/Makefile.mk
@@ -8,6 +8,7 @@
 
 ramstage-y += ec.c
 ramstage-y += mainboard.c
+ramstage-$(CONFIG_FW_CONFIG) += fw_config.c
 
 smm-$(CONFIG_HAVE_SMI_HANDLER) += smihandler.c