drm/i915: reset the GPU on context fini

It's the only way we know how to make the GPU actually forget about the
default context.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 5d9e07e..f0bd30a 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -799,7 +799,7 @@
 	return ret;
 }
 
-static int intel_gpu_reset(struct drm_device *dev)
+int intel_gpu_reset(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret = -ENODEV;