drm/i915: Fix up sdvo hpd pins for i965g/gm

Bspec seems to be full of lies, at least it disagress with reality:
Two systems corrobated that SDVO hpd bits are the same as on gen3.

v2: Update comment a bit.

Cc: Arthur Ranyan <arthur.j.runyan@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: NChris Wilson <chris@chris-wilson.co.uk>
Reported-and-tested-by: NAlex Fiestas <afiestas@kde.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=58405
Cc: stable@vger.kernel.org
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -70,15 +70,6 @@ static const u32 hpd_status_gen4[] = {
 	[HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
 };
 
-static const u32 hpd_status_i965[] = {
-	 [HPD_CRT] = CRT_HOTPLUG_INT_STATUS,
-	 [HPD_SDVO_B] = SDVOB_HOTPLUG_INT_STATUS_I965,
-	 [HPD_SDVO_C] = SDVOC_HOTPLUG_INT_STATUS_I965,
-	 [HPD_PORT_B] = PORTB_HOTPLUG_INT_STATUS,
-	 [HPD_PORT_C] = PORTC_HOTPLUG_INT_STATUS,
-	 [HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
-};
-
 static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
 	[HPD_CRT] = CRT_HOTPLUG_INT_STATUS,
 	[HPD_SDVO_B] = SDVOB_HOTPLUG_INT_STATUS_I915,
@@ -3449,13 +3440,13 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 			u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
 			u32 hotplug_trigger = hotplug_status & (IS_G4X(dev) ?
 								  HOTPLUG_INT_STATUS_G4X :
-								  HOTPLUG_INT_STATUS_I965);
+								  HOTPLUG_INT_STATUS_I915);
 
 			DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
 				  hotplug_status);
 			if (hotplug_trigger) {
 				if (hotplug_irq_storm_detect(dev, hotplug_trigger,
-							    IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965))
+							    IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i915))
 					i915_hpd_irq_setup(dev);
 				queue_work(dev_priv->wq,
 					   &dev_priv->hotplug_work);

drivers/gpu/drm/i915/i915_reg.h

@@ -1874,6 +1874,12 @@
 /* SDVO is different across gen3/4 */
 #define   SDVOC_HOTPLUG_INT_STATUS_G4X		(1 << 3)
 #define   SDVOB_HOTPLUG_INT_STATUS_G4X		(1 << 2)
+/*
+ * Bspec seems to be seriously misleaded about the SDVO hpd bits on i965g/gm,
+ * since reality corrobates that they're the same as on gen3. But keep these
+ * bits here (and the comment!) to help any other lost wanderers back onto the
+ * right tracks.
+ */
 #define   SDVOC_HOTPLUG_INT_STATUS_I965		(3 << 4)
 #define   SDVOB_HOTPLUG_INT_STATUS_I965		(3 << 2)
 #define   SDVOC_HOTPLUG_INT_STATUS_I915		(1 << 7)
@@ -1885,13 +1891,6 @@
 						 PORTC_HOTPLUG_INT_STATUS | \
 						 PORTD_HOTPLUG_INT_STATUS)
 
-#define HOTPLUG_INT_STATUS_I965			(CRT_HOTPLUG_INT_STATUS | \
-						 SDVOB_HOTPLUG_INT_STATUS_I965 | \
-						 SDVOC_HOTPLUG_INT_STATUS_I965 | \
-						 PORTB_HOTPLUG_INT_STATUS | \
-						 PORTC_HOTPLUG_INT_STATUS | \
-						 PORTD_HOTPLUG_INT_STATUS)
-
 #define HOTPLUG_INT_STATUS_I915			(CRT_HOTPLUG_INT_STATUS | \
 						 SDVOB_HOTPLUG_INT_STATUS_I915 | \
 						 SDVOC_HOTPLUG_INT_STATUS_I915 | \