Embedding net_device into structures prohibits the usage of flexible
arrays in the net_device structure. For more details, see the discussion
at [1].

Un-embed the net_devices from struct dpaa2_caam_priv_per_cpu by
converting them into pointers, and allocating them dynamically. Use the
leverage alloc_netdev_dummy() to allocate the net_device object at
dpaa2_dpseci_setup().

The free of the device occurs at dpaa2_dpseci_disable().

Link: https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/ [1]
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20240702185557.3699991-5-leitao@debian.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>