drm/i915: kill Ivybridge vblank irq vfuncs

The IVB funtions are exactly the same as the ILK ones, with the
exception of the bit register. So add IVB/HSW support to
ironlake_enable_vblank and ironlake_disable_vblank, then kill the
ivybridge functions.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
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 1d71096..e20f093 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3787,6 +3787,9 @@
 #define DE_PLANEA_FLIP_DONE_IVB		(1<<3)
 #define DE_PIPEA_VBLANK_IVB		(1<<0)
 
+#define DE_PIPE_VBLANK_ILK(pipe)	(1 << ((pipe * 8) + 7))
+#define DE_PIPE_VBLANK_IVB(pipe)	(1 << (pipe * 5))
+
 #define VLV_MASTER_IER			0x4400c /* Gunit master IER */
 #define   MASTER_INTERRUPT_ENABLE	(1<<31)