payloads/external: Add support for coreDOOM payload

coreDOOM is a port of DOOM to libpayload, based on the doomgeneric
source port. It renders the game to the coreboot linear framebuffer,
and loads WAD files from CBFS.

Tested with QEMU i440fx/q35 and a Dell Latitude E6400 using the
libgfxinit provided linear framebuffer.

Project page: https://github.com/nic3-14159/coreDOOM

Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
Change-Id: Ice0403b003a4b2717afee585f28303c2f5abea5d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57222
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Martin L Roth <gaumless@tutanota.com>

src/device/Kconfig

@@ -421,6 +421,7 @@ config WANT_LINEAR_FRAMEBUFFER
 	bool
 	default y if CHROMEOS
 	default y if PAYLOAD_TIANOCORE
+	default y if COREDOOM_SECONDARY_PAYLOAD
 
 choice
 	prompt "Framebuffer mode"