drm/i915: Parse the MIPI related VBT Block and store relevant info

Initial parsing of the VBT MIPI block. For now, just store the panel id
if found.

Note: Again there seems to be no documentation for this piece of lore.
The doc situation for byt+ is just a bad joke :(

Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
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 e262857..2cf9dab 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1065,6 +1065,11 @@
 	int edp_bpp;
 	struct edp_power_seq edp_pps;
 
+	/* MIPI DSI */
+	struct {
+		u16 panel_id;
+	} dsi;
+
 	int crt_ddc_pin;
 
 	int child_dev_num;