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/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 7f6452b..cda598d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -86,6 +86,19 @@
 };
 #define port_name(p) ((p) + 'A')
 
+enum hpd_pin {
+	HPD_NONE = 0,
+	HPD_PORT_A = HPD_NONE, /* PORT_A is internal */
+	HPD_TV = HPD_NONE,     /* TV is known to be unreliable */
+	HPD_CRT,
+	HPD_SDVO_B,
+	HPD_SDVO_C,
+	HPD_PORT_B,
+	HPD_PORT_C,
+	HPD_PORT_D,
+	HPD_NUM_PINS
+};
+
 #define I915_GEM_GPU_DOMAINS \
 	(I915_GEM_DOMAIN_RENDER | \
 	 I915_GEM_DOMAIN_SAMPLER | \