regulator: lp3971 - fix driver link error when built-in.

lp3971_i2c_remove' referenced in section `.data' of drivers/built-in.o:
defined in discarded section `.devexit.text' of drivers/built-in.o
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/lp3971.c

@@ -535,7 +535,7 @@ static struct i2c_driver lp3971_i2c_driver = {
 		.owner = THIS_MODULE,
 	},
 	.probe    = lp3971_i2c_probe,
-	.remove   = lp3971_i2c_remove,
+	.remove   = __devexit_p(lp3971_i2c_remove),
 	.id_table = lp3971_i2c_id,
 };