drm/i915: wire up SDVO hpd support on cpt/ppt

Now with Egbert Eich's hpd infrastructure rework merged this is dead
simple. And we need this to make output detection work on SDVO - with
the cleaned-up drm polling helpers outputs which claim to have hpd
support are no longer polled.

Now SDVO claims to do that, but it's not actually wired up. So just do
it.
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -46,6 +46,7 @@ static const u32 hpd_ibx[] = {
 
 static const u32 hpd_cpt[] = {
 	[HPD_CRT] = SDE_CRT_HOTPLUG_CPT,
+	[HPD_SDVO_B] = SDE_SDVOB_HOTPLUG_CPT,
 	[HPD_PORT_B] = SDE_PORTB_HOTPLUG_CPT,
 	[HPD_PORT_C] = SDE_PORTC_HOTPLUG_CPT,
 	[HPD_PORT_D] = SDE_PORTD_HOTPLUG_CPT

drivers/gpu/drm/i915/i915_reg.h

@@ -3589,7 +3589,9 @@
 #define SDE_PORTC_HOTPLUG_CPT	(1 << 22)
 #define SDE_PORTB_HOTPLUG_CPT	(1 << 21)
 #define SDE_CRT_HOTPLUG_CPT	(1 << 19)
+#define SDE_SDVOB_HOTPLUG_CPT	(1 << 18)
 #define SDE_HOTPLUG_MASK_CPT	(SDE_CRT_HOTPLUG_CPT |		\
+				 SDE_SDVOB_HOTPLUG_CPT |	\
 				 SDE_PORTD_HOTPLUG_CPT |	\
 				 SDE_PORTC_HOTPLUG_CPT |	\
 				 SDE_PORTB_HOTPLUG_CPT)