bonding: show full hw address in sysfs for slave entries

BugLink: https://bugs.launchpad.net/bugs/1830176

[ Upstream commit 18bebc6d ]

Bond expects ethernet hwaddr for its slave, but it can be longer than 6
bytes - infiniband interface for example.

 # cat /sys/devices/<skipped>/net/ib0/address
 80:00:02:08:fe:80:00:00:00:00:00:00:7c:fe:90:03:00:be:5d:e1

 # cat /sys/devices/<skipped>/net/ib0/bonding_slave/perm_hwaddr
 80:00:02:08:fe:80

So print full hwaddr in sysfs "bonding_slave/perm_hwaddr" as well.
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/bonding/bond_sysfs_slave.c

@@ -55,7 +55,9 @@ static SLAVE_ATTR_RO(link_failure_count);
 
 static ssize_t perm_hwaddr_show(struct slave *slave, char *buf)
 {
-	return sprintf(buf, "%pM\n", slave->perm_hwaddr);
+	return sprintf(buf, "%*phC\n",
+		       slave->dev->addr_len,
+		       slave->perm_hwaddr);
 }
 static SLAVE_ATTR_RO(perm_hwaddr);