Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add missing includes and remove two unused ones.

Reviewed by: loos
MFC after: 1 week

Add a new flag (ETHERSWITCH_VID_VALID) to say what vlangroups are in use.
This fix the case when etherswitch is printing the information of port 0
vlan group (in port based vlan mode) with no member ports.

Add the ETHERSWITCH_VID_VALID support to ip17x driver.

Add the ETHERSWITCH_VID_VALID support to rt8366 driver.

arswitch doesn't need to be updated as it doesn't support vlans management
yet.

Approved by: adrian (mentor)

Bring in a basic ethernet switch driver for the IP17x series of
switches.

These are notably found on some AR71xx based Mikrotik boards.

Submitted by: Luiz Otavio O Souza <loos.br@gmail.com>
Reviewed by: ray