drm/i915/opregion: Convert to using native drm_i915_private

Prefer passing struct drm_i915_private to internal interfaces as this
saves us having to dance between drm_device and our native struct. The
savings hare are small (only 70 bytes of unrequired dancing), but
progressive!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464012490-30961-1-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Jani Nikula <jani.nikula@linux.intel.com>
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 8b68c48..624e755 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -213,7 +213,7 @@
 
 	dev_priv->vbt.lvds_dither = lvds_options->pixel_dither;
 
-	ret = intel_opregion_get_panel_type(dev_priv->dev);
+	ret = intel_opregion_get_panel_type(dev_priv);
 	if (ret >= 0) {
 		WARN_ON(ret > 0xf);
 		panel_type = ret;