net: dsa: mv88e6xxx: hwtstamp: remove unnecessary range checking tests

_port_ is already known to be a valid index in the callers [1]. So
these checks are unnecessary.

[1] https://lkml.org/lkml/2018/2/16/469

Addresses-Coverity-ID: 1465287
Addresses-Coverity-ID: 1465291
Suggested-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/hwtstamp.c

@@ -179,9 +179,6 @@ int mv88e6xxx_port_hwtstamp_set(struct dsa_switch *ds, int port,
 	if (!chip->info->ptp_support)
 		return -EOPNOTSUPP;
 
-	if (port < 0 || port >= mv88e6xxx_num_ports(chip))
-		return -EINVAL;
-
 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
 		return -EFAULT;
 
@@ -206,9 +203,6 @@ int mv88e6xxx_port_hwtstamp_get(struct dsa_switch *ds, int port,
 	if (!chip->info->ptp_support)
 		return -EOPNOTSUPP;
 
-	if (port < 0 || port >= mv88e6xxx_num_ports(chip))
-		return -EINVAL;
-
 	return copy_to_user(ifr->ifr_data, config, sizeof(*config)) ?
 		-EFAULT : 0;
 }
@@ -255,9 +249,6 @@ static u8 *mv88e6xxx_should_tstamp(struct mv88e6xxx_chip *chip, int port,
 	if (!chip->info->ptp_support)
 		return NULL;
 
-	if (port < 0 || port >= mv88e6xxx_num_ports(chip))
-		return NULL;
-
 	hdr = parse_ptp_header(skb, type);
 	if (!hdr)
 		return NULL;