drm/i915: Set alternate aux for DDI-E

There is no correspondent Aux channel for DDI-E.

So we need to rely on VBT to let us know witch one
is being used instead.

v2: Removing some trailing spaces and giving proper
credit to Xiong that added a nice way to avoid port
conflicts by setting supports_dp = 0 when using
equivalent aux for DDI-E.

Credits-to: Xiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Xiong Zhang <xiong.y.zhang@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 4e9f7b1..a8ac36d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1409,6 +1409,11 @@
 	MODESET_SUSPENDED,
 };
 
+#define DP_AUX_A 0x40
+#define DP_AUX_B 0x10
+#define DP_AUX_C 0x20
+#define DP_AUX_D 0x30
+
 struct ddi_vbt_port_info {
 	/*
 	 * This is an index in the HDMI/DVI DDI buffer translation table.
@@ -1421,6 +1426,8 @@
 	uint8_t supports_dvi:1;
 	uint8_t supports_hdmi:1;
 	uint8_t supports_dp:1;
+
+	uint8_t alternate_aux_channel;
 };
 
 enum psr_lines_to_wait {