mb/amd/majolica: Enable required devices in devicetree

Most devices are now disabled by default in the chipset. Enable the
iGPU and two XHCI controllers that are required to boot the board.

BUG=b:180528708
TEST=To be tested

Signed-off-by: Mathew King <mathewk@chromium.org>
Change-Id: I54a4547217fb8e9f67fc0c8e1e36e96dfaae331c
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51095
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/amd/majolica/devicetree.cb

@@ -3,6 +3,11 @@
 chip soc/amd/cezanne
 
 	device domain 0 on
+		device ref gpp_bridge_a on  # Internal GPP Bridge 0 to Bus A
+			device ref gfx on end # Internal GPU (GFX)
+			device ref xhci_0 on end # USB 3.1 (USB0)
+			device ref xhci_1 on end # USB 3.1 (USB1)
+		end
 	end
 
 end