MFC: r233274

MFC: r233274

Remove remnants of ATA_LOCKING uses in the ATA_CAM case and wrap it
along with functions, SYSCTLs and tunables that are not used with
ATA_CAM in #ifndef ATA_CAM, similar to the existing #ifdef'ed ATA_CAM
code for the other way around. This makes it easier to understand
which parts of ata(4) actually are used in the new world order and
to later on remove the !ATA_CAM bits. It also makes it obvious that
there is something fishy with the C-bus front-end as well as in the
ATP850 support, as these used ATA_LOCKING which is defunct in the
ATA_CAM case. When fixing the former, ATA_LOCKING probably needs to
be brought back in some form or other.

Reviewed by:	mav

git-svn-id: svn://svn.freebsd.org/base/stable/9@233715 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f