soc/intel/icelake: Add ENABLE_DISPLAY_OVER_EXT_PCIE_GFX kconfig

This patch creates new kconfig option to bring display over external
PCI based GFX card. This kconfig to select required kconfig which are
not default selected by VGA_ROM_RUN to launch legacy oprom from pci
based GFX card.

Change-Id: I8ebde69e38defbe3321eb5e5bbd632c209ae2cd8
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33738
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Wonkyu Kim <wonkyu.kim@intel.com>
Reviewed-by: V Sowmya <v.sowmya@intel.com>
diff --git a/src/soc/intel/icelake/Kconfig b/src/soc/intel/icelake/Kconfig
index 5dca44b..99000bb 100644
--- a/src/soc/intel/icelake/Kconfig
+++ b/src/soc/intel/icelake/Kconfig
@@ -205,4 +205,15 @@
 	depends on FSP_USE_REPO
 	default "3rdparty/fsp/IceLakeFspBinPkg/Fsp.fd"
 
+config ENABLE_DISPLAY_OVER_EXT_PCIE_GFX
+	bool "Enable display over external PCIE GFX card"
+	select ALWAYS_LOAD_OPROM
+	help
+	  It's possible to bring display through external graphics card over PCIE
+	  in coreboot. This option enables graphics initialization with external
+	  graphics card.
+
+	  Selected by mainboard that runs OpRom to perform display
+	  initialization over attached PCIe GFX card.
+
 endif