drm/i915: No need to wait for idle on L3 remap

As the L3 remapping is applied before the next execution, there is no
need to wait until all previous uses are idle, the application will not
occur any sooner.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466776558-21516-5-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_sysfs.c

@@ -227,13 +227,6 @@ i915_l3_write(struct file *filp, struct kobject *kobj,
 		}
 	}
 
-	ret = i915_gpu_idle(drm_dev);
-	if (ret) {
-		kfree(temp);
-		mutex_unlock(&drm_dev->struct_mutex);
-		return ret;
-	}
-
 	/* TODO: Ideally we really want a GPU reset here to make sure errors
 	 * aren't propagated. Since I cannot find a stable way to reset the GPU
 	 * at this point it is left as a TODO.