mb/amd/onyx: Add FMD file and update romsize

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Change-Id: Idd6f711f5ca5c8a421c0c38edd404b1900bb29b4
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76497
Reviewed-by: Martin L Roth <gaumless@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/amd/onyx/Kconfig

@@ -4,6 +4,11 @@ config BOARD_SPECIFIC_OPTIONS
 	def_bool y
 	select SOC_AMD_GENOA
 	select MISSING_BOARD_RESET
+	select BOARD_ROMSIZE_KB_32768
+
+config FMDFILE
+	default "src/mainboard/amd/onyx/board.fmd"
+
 
 config MAINBOARD_DIR
 	default "amd/onyx"

src/mainboard/amd/onyx/board.fmd

@@ -0,0 +1,8 @@
+FLASH 32M {
+	BIOS 16M {
+		COREBOOT(CBFS)
+		FMAP 4K
+		RW_VPD 8K
+		RO_VPD 8K
+	}
+}