drm: Print bad user modes

Print out the modeline when we reject a bad user mode. Avoids having to
guess why it was rejected.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180611193403.16118-2-ville.syrjala@linux.intel.com
Reviewed-by: Harry Wentland <harry.wentland@amd.com>

drivers/gpu/drm/drm_crtc.c

@@ -649,7 +649,9 @@ retry:
 
 		ret = drm_mode_convert_umode(dev, mode, &crtc_req->mode);
 		if (ret) {
-			DRM_DEBUG_KMS("Invalid mode\n");
+			DRM_DEBUG_KMS("Invalid mode (ret=%d, status=%s)\n",
+				      ret, drm_get_mode_status_name(mode->status));
+			drm_mode_debug_printmodeline(mode);
 			goto out;
 		}