Merge branch 'marvell-prestera-firmware-3-0'

Vadym Kochan says:

====================
Marvell Prestera Switchdev initial updates for firmware version 3.0

This series adds minimal support for firmware version 3.0 which
has such changes like:

    - initial routing support

    - LAG support

    - events interrupt handling changes

Changes just make able to work with new firmware version but
supported features in driver will be added later.

New firmware version was recently merged into linux-firmware tree.

Added ability of loading previous fw major version if the latest one
is missing, also add support for previous FW ABI.

PATCH -> RFC:
    1) Load previous fw version if the latest one is missing (suggested by Andrew Lunn)

    2) Add support for previous FW ABI version (suggested by Andrew Lunn)

RFC v2:
    1) Get rid of automatic decrementing of
       major version but hard code it.

    2) Print error message with file path if
       previous FW could not be loaded.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>