common/sfc_efx/base: do not validate MAE action COUNT order

common/sfc_efx/base: do not validate MAE action COUNT order

In DPDK + Open vSwitch use case, action COUNT is always the
first one to be added. In particular, it goes before action
DECAP in that use case. The current code enforces the right
order (DECAP goes before COUNT), and this provokes failures.
As an exception, do not validate the order for action COUNT.

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Andy Moreton <amoreton@xilinx.com>