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: Keith Packard <keithp@keithp.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a087e1b..d5c7c7b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3019,7 +3019,7 @@
 	/* 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;
 	}