Revert "drm/i915: Work around gen7 BLT ring synchronization issues."

This reverts commit 42ff6572.

New forcewake voodoo makes this no longer necessary.
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NKeith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -804,17 +804,6 @@ ring_add_request(struct intel_ring_buffer *ring,
 	return 0;
 }
 
-static bool
-gen7_blt_ring_get_irq(struct intel_ring_buffer *ring)
-{
-	/* The BLT ring on IVB appears to have broken synchronization
-	 * between the seqno write and the interrupt, so that the
-	 * interrupt appears first.  Returning false here makes
-	 * i915_wait_request() do a polling loop, instead.
-	 */
-	return false;
-}
-
 static bool
 gen6_ring_get_irq(struct intel_ring_buffer *ring, u32 gflag, u32 rflag)
 {
@@ -1600,8 +1589,5 @@ int intel_init_blt_ring_buffer(struct drm_device *dev)
 
 	*ring = gen6_blt_ring;
 
-	if (IS_GEN7(dev))
-		ring->irq_get = gen7_blt_ring_get_irq;
-
 	return intel_init_ring_buffer(dev, ring);
 }