drm/i915: don't init DP or HDMI when not supported by DDI port

There's no reason to init a DP connector if the encoder just supports
HDMI: we'll just waste hundreds and hundreds of cycles trying to do DP
AUX transactions to detect if there's something there. Same goes for a
DP connector that doesn't support HDMI, but I'm not sure these
actually exist.

v2: - Use bit fields
    - Remove useless identation level
    - Replace DRM_ERROR with DRM_DEBUG_KMS

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com> (v1)
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 2eca286..b1485a0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1059,6 +1059,10 @@
 
 struct ddi_vbt_port_info {
 	uint8_t hdmi_level_shift;
+
+	uint8_t supports_dvi:1;
+	uint8_t supports_hdmi:1;
+	uint8_t supports_dp:1;
 };
 
 struct intel_vbt_data {