hwmon: (f75375s) Do not overwrite values read from registers

All bits in the values read from registers to be used for the next
write were getting overwritten, avoid doing so to not mess with the
current configuration.
Signed-off-by: NGuillem Jover <guillem@hadrons.org>
Cc: Riku Voipio <riku.voipio@iki.fi>
Cc: stable@kernel.org
Signed-off-by: NJean Delvare <khali@linux-fr.org>

drivers/hwmon/f75375s.c

@@ -298,7 +298,7 @@ static int set_pwm_enable_direct(struct i2c_client *client, int nr, int val)
 		return -EINVAL;
 
 	fanmode = f75375_read8(client, F75375_REG_FAN_TIMER);
-	fanmode = ~(3 << FAN_CTRL_MODE(nr));
+	fanmode &= ~(3 << FAN_CTRL_MODE(nr));
 
 	switch (val) {
 	case 0: /* Full speed */
@@ -350,7 +350,7 @@ static ssize_t set_pwm_mode(struct device *dev, struct device_attribute *attr,
 
 	mutex_lock(&data->update_lock);
 	conf = f75375_read8(client, F75375_REG_CONFIG1);
-	conf = ~(1 << FAN_CTRL_LINEAR(nr));
+	conf &= ~(1 << FAN_CTRL_LINEAR(nr));
 
 	if (val == 0)
 		conf |= (1 << FAN_CTRL_LINEAR(nr)) ;