net/mlx5e: Support IPsec acquire default SA

During XFRM stack acquire flow, a default SA is created to be updated
later, once acquire netlink message is handled in user space.

This SA is also passed to IPsec offload supporting driver, however this
SA acts only as placeholder and does not have context suitable for
offloading in HW yet. Identify this kind of SA by special offload flag
(XFRM_DEV_OFFLOAD_FLAG_ACQ), and create a SW only context.

In such cases with special mark so it won't be installed in HW in addition
flow and on remove/delete free this SW only context.

Signed-off-by: Raed Salem <raeds@nvidia.com>
Link: https://lore.kernel.org/r/8f36d6b61631dcd73fef0a0ac623456030bc9db0.1678714336.git.leon@kernel.org


Signed-off-by: Leon Romanovsky <leon@kernel.org>