drm/i915: GPIO/GMBUS registers need an offset on VLV

GPIO/GMBUS registers must be offset on VLV, so simply
adjust gpio_mmio_base to include the correct offset.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_i2c.c

@@ -515,6 +515,8 @@ int intel_setup_gmbus(struct drm_device *dev)
 
 	if (HAS_PCH_SPLIT(dev))
 		dev_priv->gpio_mmio_base = PCH_GPIOA - GPIOA;
+	else if (IS_VALLEYVIEW(dev))
+		dev_priv->gpio_mmio_base = VLV_DISPLAY_BASE;
 	else
 		dev_priv->gpio_mmio_base = 0;