drm/i915: Use '1' instead of FORCEWAKE_KERNEL for ST force wake

Use the number '1' instead of FORCEWAKE_KERNEL when requesting single
thread force wake since there is only one bit in the register. Using
the FORCEWAKE_KERNEL name might give someone the wrong impression.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -4282,7 +4282,7 @@ static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
 			    FORCEWAKE_ACK_TIMEOUT_MS))
 		DRM_ERROR("Timed out waiting for forcewake old ack to clear.\n");
 
-	I915_WRITE_NOTRACE(FORCEWAKE, FORCEWAKE_KERNEL);
+	I915_WRITE_NOTRACE(FORCEWAKE, 1);
 	POSTING_READ(ECOBUS); /* something from same cacheline, but !FORCEWAKE */
 
 	if (wait_for_atomic((I915_READ_NOTRACE(forcewake_ack) & 1),