net: aquantia: Fix IFF_ALLMULTI flag functionality

It was noticed that NIC always pass all multicast traffic to the host
regardless of IFF_ALLMULTI flag on the interface.
The rule in MC Filter Table in NIC, that is configured to accept any
multicast packets, is turning on if IFF_MULTICAST flag is set on the
interface. It leads to passing all multicast traffic to the host.
This fix changes the condition to turn on that rule by checking
IFF_ALLMULTI flag as it should.

Fixes: b21f502f

 ("net:ethernet:aquantia: Fix for multicast filter handling.")
Signed-off-by: Dmitry Bogdanov <dmitry.bogdanov@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>