drm/i915: Ignore GPU wedged errors while pinning scanout buffers

Failing to pin a scanout buffer will most likely lead to a black
screen, so if the GPU is wedged, then just let the pin happen and hope
that things work out OK.
Signed-off-by: NKeith Packard <keithp@keithp.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_gem.c

@@ -3019,7 +3019,7 @@ i915_gem_object_set_to_display_plane(struct drm_i915_gem_object *obj,
 	/* Currently, we are always called from an non-interruptible context. */
 	if (pipelined != obj->ring) {
 		ret = i915_gem_object_wait_rendering(obj);
-		if (ret)
+		if (ret == -ERESTARTSYS)
 			return ret;
 	}