drm/i915: only enable hotplug for detected outputs

This patch changes around our hotplug enable code a bit to only enable
it for ports we actually detect and initialize.  This prevents problems
with stuck or spurious interrupts on outputs that aren't actually wired
up, and is generally more correct.

Fixes FDO bug #23183.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 4e7aa8b..1349d9f 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1402,14 +1402,20 @@
 			break;
 		case DP_B:
 		case PCH_DP_B:
+			dev_priv->hotplug_supported_mask |=
+				HDMIB_HOTPLUG_INT_STATUS;
 			name = "DPDDC-B";
 			break;
 		case DP_C:
 		case PCH_DP_C:
+			dev_priv->hotplug_supported_mask |=
+				HDMIC_HOTPLUG_INT_STATUS;
 			name = "DPDDC-C";
 			break;
 		case DP_D:
 		case PCH_DP_D:
+			dev_priv->hotplug_supported_mask |=
+				HDMID_HOTPLUG_INT_STATUS;
 			name = "DPDDC-D";
 			break;
 	}