drm/i915: Introduce enableddisabled helper

Similar to existing yesno and onoff and use it throughout the code.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1479385814-2358-2-git-send-email-tvrtko.ursulin@linux.intel.com
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 14c3ae5..e207dc6 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -347,8 +347,7 @@ void intel_set_memory_cxsr(struct drm_i915_private *dev_priv, bool enable)
 		return;
 	}
 
-	DRM_DEBUG_KMS("memory self-refresh is %s\n",
-		      enable ? "enabled" : "disabled");
+	DRM_DEBUG_KMS("memory self-refresh is %s\n", enableddisabled(enable));
 }