mfd: Remove unneeded ret value checking for max8998 register updates

i2c_smbus_write_byte_data() returns zero or negative value,
therefore no need to check if ret is greater than zero or not.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/max8998.c

@@ -110,8 +110,6 @@ int max8998_update_reg(struct i2c_client *i2c, u8 reg, u8 val, u8 mask)
 		u8 old_val = ret & 0xff;
 		u8 new_val = (val & mask) | (old_val & (~mask));
 		ret = i2c_smbus_write_byte_data(i2c, reg, new_val);
-		if (ret >= 0)
-			ret = 0;
 	}
 	mutex_unlock(&max8998->iolock);
 	return ret;