net: atlantic: add support for FW 4.x

This patch adds support for FW 4.x, which is about to get into the
production for some products.
4.x is mostly compatible with 3.x, save for soft reset, which requires
the acquisition of 2 additional semaphores.
Other differences (e.g. absence of PTP support) are handled via
capabilities.

Note: 4.x targets specific products only. 3.x is still the main firmware
branch, which should be used by most users (at least for now).

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