drm/i915: Call gen5_gt_irq_reset() from valleyview_irq_uninstall()

Looks like we forgot to call gen5_gt_irq_reset() for vlv in the
uninstall phase. Do so.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -3588,6 +3588,8 @@ static void valleyview_irq_uninstall(struct drm_device *dev)
 
 	I915_WRITE(VLV_MASTER_IER, 0);
 
+	gen5_gt_irq_reset(dev);
+
 	for_each_pipe(dev_priv, pipe)
 		I915_WRITE(PIPESTAT(pipe), 0xffff);