DRM/I915: Add enum hpd_pin to intel_encoder.

To clean up hotplug support we add a new enum to intel_encoder:
enum hpd_pin. It allows the encoder to request a hpd line but leave
the details which IRQ is responsible on which chipset generation
to i915_irq.c.
This way requesting hotplug support will become really simple on
the encoder/connector level.

Signed-off-by: Egbert Eich <eich@suse.de>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 2474b1b..6d92aeb 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -988,17 +988,21 @@
 	switch (port) {
 	case PORT_B:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPB;
+		intel_encoder->hpd_pin = HPD_PORT_B;
 		dev_priv->hotplug_supported_mask |= PORTB_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_C:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPC;
+		intel_encoder->hpd_pin = HPD_PORT_C;
 		dev_priv->hotplug_supported_mask |= PORTC_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_D:
 		intel_hdmi->ddc_bus = GMBUS_PORT_DPD;
+		intel_encoder->hpd_pin = HPD_PORT_D;
 		dev_priv->hotplug_supported_mask |= PORTD_HOTPLUG_INT_STATUS;
 		break;
 	case PORT_A:
+		intel_encoder->hpd_pin = HPD_PORT_A;
 		/* Internal port only for eDP. */
 	default:
 		BUG();