drm/i915/uc: Add params for specifying firmware

`guc_firmware_path` and `huc_firmware_path` module parameters are added.

Using the parameter disables version checks and loads desired firmware
instead of the default one.

v2: make params unsafe && notice about disabled fw check (J. Lahtinen)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
index f8c9e31..d1d183b 100644
--- a/drivers/gpu/drm/i915/intel_guc_loader.c
+++ b/drivers/gpu/drm/i915/intel_guc_loader.c
@@ -407,7 +407,11 @@ int intel_guc_select_fw(struct intel_guc *guc)
 	guc->fw.load_status = INTEL_UC_FIRMWARE_NONE;
 	guc->fw.fw = INTEL_UC_FW_TYPE_GUC;
 
-	if (IS_SKYLAKE(dev_priv)) {
+	if (i915.guc_firmware_path) {
+		guc->fw.path = i915.guc_firmware_path;
+		guc->fw.major_ver_wanted = 0;
+		guc->fw.minor_ver_wanted = 0;
+	} else if (IS_SKYLAKE(dev_priv)) {
 		guc->fw.path = I915_SKL_GUC_UCODE;
 		guc->fw.major_ver_wanted = SKL_FW_MAJOR;
 		guc->fw.minor_ver_wanted = SKL_FW_MINOR;