soc/intel: Hook up SOC_INTEL_DISABLE_IGD to InternalGfx UPD

Commit 0591348833 introduced this Kconfig
option inside soc/intel/common scope. However, it was only hooked up in
commit d74cd60b81 for Alder Lake, and in
commit 99157c1f4a for Tiger Lake. Hook up
the `SOC_INTEL_DISABLE_IGD` Kconfig option to all other platforms which
have the `InternalGfx` UPD.

Change-Id: Icd1379a835b445a6d4b028ebde5a3e355ee5b67b
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52100
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-by:  Felix Singer <felixsinger@posteo.net>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Subrata Banik <subrata.banik@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/skylake/romstage/fsp_params.c

@@ -112,7 +112,7 @@ static void soc_primary_gfx_config_params(FSP_M_CONFIG *m_cfg,
 	const struct device *dev;
 
 	dev = pcidev_path_on_root(SA_DEVFN_IGD);
-	m_cfg->InternalGfx = dev && dev->enabled;
+	m_cfg->InternalGfx = !CONFIG(SOC_INTEL_DISABLE_IGD) && dev && dev->enabled;
 
 	/*
 	 * If iGPU is enabled, set IGD stolen size to 64MB. The FBC