net: atlantic: A2 ingress / egress hw configuration

Chip generations are mostly compatible register-wise, but there are still
some differences. Therefore we've made some of first generation (A1) code
non-static to re-use it where possible.

Some pieces are A2 specific, in which case we redefine/extend such APIs.

Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: Mark Starovoytov <mstarovoitov@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>