regulator: tps80031: remove unnecessary parentheses

Remove unnecessary parentheses in order to fix the following
checkpatch error.

ERROR: return is not a function, parentheses are not required

Signed-off-by: Jingoo Han <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/tps80031-regulator.c

···
 			ri->rinfo->state_reg, ret);
 		return ret;
 	}
-	return ((reg_val & TPS80031_STATE_MASK) == TPS80031_STATE_ON);
+	return (reg_val & TPS80031_STATE_MASK) == TPS80031_STATE_ON;
 }
 
 static int tps80031_reg_enable(struct regulator_dev *rdev)