soc/intel: Add Alder Lake's GT device ID

Add Alder Lake specific graphics device ID. The document# 641765 lists
the id 0x46a8.

TEST=Verify boot on brya

Signed-off-by: Sridhar Siricilla <sridhar.siricilla@intel.com>
Change-Id: I6f36256505a3e07c6197079ea2013991e841401b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55256
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Maulik V Vaghela <maulik.v.vaghela@intel.com>
Reviewed-by: Ronak Kanabar <ronak.kanabar@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/intel/common/block/graphics/graphics.c b/src/soc/intel/common/block/graphics/graphics.c
index 80f13c6..cbeffce 100644
--- a/src/soc/intel/common/block/graphics/graphics.c
+++ b/src/soc/intel/common/block/graphics/graphics.c
@@ -299,6 +299,7 @@
 	PCI_DEVICE_ID_INTEL_ADL_P_GT2_1,
 	PCI_DEVICE_ID_INTEL_ADL_P_GT2_2,
 	PCI_DEVICE_ID_INTEL_ADL_P_GT2_3,
+	PCI_DEVICE_ID_INTEL_ADL_P_GT2_4,
 	PCI_DEVICE_ID_INTEL_ADL_S_GT1,
 	PCI_DEVICE_ID_INTEL_ADL_M_GT1,
 	0,