drm/i915: Enable HDMI on DDI-E

DDI-E doesn't have the correspondent GMBUS pin.

We rely on VBT to tell us which one it being used instead.

The DVI/HDMI on shared port couldn't exist.

This patch isn't tested without hardware wchich has HDMI
on DDI-E.

v2: fix trailing whitespace
v3: MISSING_CASE take place of BUG()

Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 089459b..9b9bd2e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1416,6 +1416,10 @@
 #define DP_AUX_C 0x20
 #define DP_AUX_D 0x30
 
+#define DDC_PIN_B  0x05
+#define DDC_PIN_C  0x04
+#define DDC_PIN_D  0x06
+
 struct ddi_vbt_port_info {
 	/*
 	 * This is an index in the HDMI/DVI DDI buffer translation table.
@@ -1430,6 +1434,7 @@
 	uint8_t supports_dp:1;
 
 	uint8_t alternate_aux_channel;
+	uint8_t alternate_ddc_pin;
 
 	uint8_t dp_boost_level;
 	uint8_t hdmi_boost_level;