drm/i915: extract backlight minimum brightness from VBT

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 30b23bf..12ab320 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1270,6 +1270,7 @@
 		u16 pwm_freq_hz;
 		bool present;
 		bool active_low_pwm;
+		u8 min_brightness;	/* min_brightness/255 of max */
 	} backlight;
 
 	/* MIPI DSI */