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: Chris Wilson <chris@chris-wilson.co.uk>
Reported-and-tested-by: Alex Fiestas <afiestas@kde.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=58405
Cc: stable@vger.kernel.org
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 2102ff3..137be4c 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/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 | \