net/mlx5: fix header modify action validation

net/mlx5: fix header modify action validation

The header modify actions number supported now has some limitation,
and it is decided by both driver and hardware. If the configuration
is different or the table to insert the flow is different, the result
might be different if the flow contains header modify actions.
Currently, the actual action number could only be calculated in the
later stage called translate, from user specified value to the driver
format. And the action numbers checking is missed in the flow
validation. So PMD will return incorrect result to indicate the
flow actions are valid by rte_flow_validate but then it will fail
when calling rte_flow_create.

Adding some simple checking in the validation will help to get rid
of this incorrect checking. Most of the actions will only consume 1
SW action field except the MAC address and IPv6 address. And from
SW POV, the maximal action fields for these will be consumed even if
only part of such field will be modified because that there is no
mask in the flow actions and the mask will always be all ONEs.

The metering or extra metadata supports will cost one more action.

Fixes: 9597330c6844 ("net/mlx5: update modify header action translator")
Cc: stable@dpdk.org
Signed-off-by: Bing Zhao <bingz@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>