net/mlx5e: Support IPsec packet offload for TX in switchdev mode

The IPsec encryption is done at the last, so add new prio for IPsec
offload in FDB, and put it just lower than the slow path prio and
higher than the per-vport prio.
Three levels are added for TX. The first one is for ip xfrm policy.
The sa table is created in the second level for ip xfrm state. The
status table is created at the last to count the number of packets
encrypted.
The rules, which forward packets to uplink, are changed to forward
them to IPsec TX tables first. These rules are restored after those
tables are destroyed, which is done immediately when there is no
reference to them, just as what does in legacy mode. The support for
slow path is added here, by refreshing uplink's channels. But, the
handling for TC fast path, which is more complicated, will be added
later. Besides, reg c4 is used instead to match reqid.

Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/cfd0e6ffaf0b8c55ebaa9fb0649b7c504b6b8ec6.1690802064.git.leon@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>