net/bonding: check code of allmulticast mode switch

rte_eth_allmulticast_enable()/rte_eth_allmulticast_disable() return
value was changed from void to int, so this patch modify usage
of these functions across net/bonding
according to new return type.

Signed-off-by: Ivan Ilchenko <ivan.ilchenko@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>