mfd: Staticise WM8994 PM ops

They're not exported.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/wm8994-core.c b/drivers/mfd/wm8994-core.c
index 5220af2..749c31d 100644
--- a/drivers/mfd/wm8994-core.c
+++ b/drivers/mfd/wm8994-core.c
@@ -640,7 +640,8 @@
 };
 MODULE_DEVICE_TABLE(i2c, wm8994_i2c_id);
 
-UNIVERSAL_DEV_PM_OPS(wm8994_pm_ops, wm8994_suspend, wm8994_resume, NULL);
+static UNIVERSAL_DEV_PM_OPS(wm8994_pm_ops, wm8994_suspend, wm8994_resume,
+			    NULL);
 
 static struct i2c_driver wm8994_i2c_driver = {
 	.driver = {