net/mlx5e: Clear mirred devices array if the rule is split

In the cited commit, the mirred devices are recorded and checked while
parsing the actions. In order to avoid system crash, the duplicate
action in a single rule is not allowed.

But the rule is actually break down into several FTEs in different
tables, for either mirroring, or the specified types of actions which
use post action infrastructure.

It will reject certain action list by mistake, for example:
    actions:enp8s0f0_1,set(ipv4(ttl=63)),enp8s0f0_0,enp8s0f0_1.
Here the rule is split to two FTEs because of pedit action.

To fix this issue, when parsing the rule actions, reset if_count to
clear the mirred devices array if the rule is split to multiple
FTEs, and then the duplicate checking is restarted.

Fixes: 554fe75c

 ("net/mlx5e: Avoid duplicating rule destinations")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>