drm/i915: Use FORCEWAKE_KERNEL instead of hardcoded number in MT forcewake ACK

The MT forcewake ACK register also has a corresponding bit to each of
the bits in the MT forcewake register. Use the define we have for the
bit we care about instead of a hardcoded number.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -4308,7 +4308,7 @@ static void __gen6_gt_force_wake_mt_get(struct drm_i915_private *dev_priv)
 	else
 		forcewake_ack = FORCEWAKE_MT_ACK;
 
-	if (wait_for_atomic((I915_READ_NOTRACE(forcewake_ack) & 1) == 0,
+	if (wait_for_atomic((I915_READ_NOTRACE(forcewake_ack) & FORCEWAKE_KERNEL) == 0,
 			    FORCEWAKE_ACK_TIMEOUT_MS))
 		DRM_ERROR("Timed out waiting for forcewake old ack to clear.\n");
 
@@ -4316,7 +4316,7 @@ static void __gen6_gt_force_wake_mt_get(struct drm_i915_private *dev_priv)
 	/* something from same cacheline, but !FORCEWAKE_MT */
 	POSTING_READ(ECOBUS);
 
-	if (wait_for_atomic((I915_READ_NOTRACE(forcewake_ack) & 1),
+	if (wait_for_atomic((I915_READ_NOTRACE(forcewake_ack) & FORCEWAKE_KERNEL),
 			    FORCEWAKE_ACK_TIMEOUT_MS))
 		DRM_ERROR("Timed out waiting for forcewake to ack request.\n");
 
@@ -4406,13 +4406,13 @@ static void vlv_force_wake_reset(struct drm_i915_private *dev_priv)
 
 static void vlv_force_wake_get(struct drm_i915_private *dev_priv)
 {
-	if (wait_for_atomic((I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & 1) == 0,
+	if (wait_for_atomic((I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & FORCEWAKE_KERNEL) == 0,
 			    FORCEWAKE_ACK_TIMEOUT_MS))
 		DRM_ERROR("Timed out waiting for forcewake old ack to clear.\n");
 
 	I915_WRITE_NOTRACE(FORCEWAKE_VLV, _MASKED_BIT_ENABLE(FORCEWAKE_KERNEL));
 
-	if (wait_for_atomic((I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & 1),
+	if (wait_for_atomic((I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & FORCEWAKE_KERNEL),
 			    FORCEWAKE_ACK_TIMEOUT_MS))
 		DRM_ERROR("Timed out waiting for forcewake to ack request.\n");