mlxsw: spectrum: Don't sleep during ndo_get_phys_port_name()

When rtnl_fill_ifinfo() is called for a certain netdevice it queries its
various parameters such as switch id and physical port name. The
function might get called in an atomic context, which means the
underlying driver must not sleep during the query operation.

Don't query the device and sleep during ndo_get_phys_port_name(), but
instead store the needed parameters in port creation time.

Fixes: 2bf9a586 ("mlxsw: spectrum: Add support for physical port names")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>