Upgrade ENA to v2.4.0

Upgrade ENA to v2.4.0

Approved by: re

ena: change ENA C++-style comment into C-style

According to man style(9), only C-style comments should be used.

Submitted by: Michal Krawczyk <mk@semihalf.com>
Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.

(cherry picked from commit 438c9e3cf89403628ec237cfecdd0538f208087b)

ena: add support for the large LLQ headers in ENA

Default LLQ (Low-latency queue) maximum header size is 96 bytes and can
be too small for some types of packets - like IPv6 packets with multiple
extension. This can be fixed, by using large LLQ headers.

If the device supports larger LLQ headers, the user can activate this
feature by setting sysctl tunable 'hw.ena.force_large_llq_header' to '1'
in the /boot/loader.conf file.

In case the device isn't supporting this feature, the default value (96B)
will be used.

Submitted by: Michal Krawczyk <mk@semihalf.com>
Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.

(cherry picked from commit beaadec9eaec8e6b266faff3b0880a141728fcef)

ena: remove surplus NULL checks when freeing ENA resources

Calling free on a NULL pointer is valid, as appropriate check is already
done internally:

/* free(NULL, ...) does nothing */
if (addr == NULL)
    return;

Submitted by: Artur Rojek <ar@semihalf.com>
Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.

(cherry picked from commit ddec69e6a796283497ebada0569f34bd41bbdf37)

ena: hide sysctl nodes for unused ENA queues

IO queue related attributes are registered statically at driver attach
with the rest of the ENA specific sysctl nodes. However, the number of
queues can be changed at runtime via the `ena_sysctl_io_queues_nb`
request, leading to a potential exposure of attributes for non-existing
queues.

Introduce a new `ena_sysctl_update_queue_node_nb` function, which
updates the sysctl nodes after the number of queues is altered.
This happens by either registering or unregistering node specific oids,
based on a delta between the previous and current queue count.

NOTE: All unregistered oids must be registered again before the driver
detach, e.g. by another call to this function.

Submitted by: Artur Rojek <ar@semihalf.com>
Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.

(cherry picked from commit 0e7d31f63b9db869c91228d8ed1e984bdee2b931)

Merge tag 'vendor/ena-com/2.4.0'

Update the driver in order not to break its compilation
and make use of the new ENA logging system

Migrate platform code to the new logging system provided by ena_com
layer.

Make ENA_INFO the new default log level.

Remove all explicit use of `device_printf`, all new logs requiring one
of the log macros to be used.

(cherry picked from commit 3fc5d816f8831d6fc2816ac97bd78dc486cd080c)

Update ENA driver man page

Bring the obsolete man page up to date:
* update diagnostic error messages
* add documentation of loader tunables
* document netmap support
* add a driver history section
* update the contact information

Submitted by: Artur Rojek <ar@semihalf.com>
Submitted by: Michal Krawczyk <mk@semihalf.com>
Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.

(cherry picked from commit e34856a2c44a45512463aed0d1794f34258c66ee)

Update ENA version to v2.4.0

Some of the changes in this release:
* Large LLQ headers,
* Bug/stability fixes,
* Change of the README/Documentation.

Submitted by: Michal Krawczyk <mk@semihalf.com>
Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.

(cherry picked from commit 93f0df457bf1d0e5f71839ab969c94d1f95813fb)