mlxsw: core: Reset firmware after flash during driver initialization

After flashing new firmware during the driver initialization flow (reload
or not), the driver should do a firmware reset when it gets -EAGAIN in
order to load the new one.

Signed-off-by: Shalom Toledo <shalomt@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>