drm/xe/gsc: Add status check during gsc header readout

Before checking if data is present in the message reply check the
status in header and see if it indicates any error.

--v2
- Use drm_err() instead of drm_dbg_kms() [Daniele]

--v3
- Use &xe->drm in drm_err to make it more cleaner [Daniele]

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240124045248.687023-1-suraj.kandpal@intel.com

drivers/gpu/drm/xe/xe_gsc_submit.c

@@ -125,11 +125,18 @@ int xe_gsc_read_out_header(struct xe_device *xe,
 {
 	u32 marker = mtl_gsc_header_rd(xe, map, offset, validity_marker);
 	u32 size = mtl_gsc_header_rd(xe, map, offset, message_size);
+	u32 status = mtl_gsc_header_rd(xe, map, offset, status);
 	u32 payload_size = size - GSC_HDR_SIZE;
 
 	if (marker != GSC_HECI_VALIDITY_MARKER)
 		return -EPROTO;
 
+	if (status != 0) {
+		drm_err(&xe->drm, "GSC header readout indicates error: %d\n",
+			status);
+		return -EINVAL;
+	}
+
 	if (size < GSC_HDR_SIZE || payload_size < min_payload_size)
 		return -ENODATA;