drm/i915: Remove the WARN when failing to set tiling.

We generally issue an error message at the point of failure, and so this
warning with a fairly pointless stacktrace is superfluous and ugly.
Needless to say, the common trigger for this WARN happens to be EIO
where this is pure noise.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_gem_tiling.c

@@ -333,8 +333,6 @@ i915_gem_set_tiling(struct drm_device *dev, void *data,
 			i915_gem_release_mmap(obj);
 
 		if (ret != 0) {
-			WARN(ret != -ERESTARTSYS,
-			     "failed to reset object for tiling switch");
 			args->tiling_mode = obj_priv->tiling_mode;
 			args->stride = obj_priv->stride;
 			goto err;