Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r241844:
remove duplicate semicolons where possible.

Approved by: cperciva (implicit)

MFC 233040,233198,233870,234183:
Add OFED and the associated options and drivers to x86 LINT builds:
- Fix build with INET6 disabled.
- Fix build of OFED bits with debugging options enabled.
- Fix build on i386.
- Mark 'sdp' as requiring 'inet'.
- Always include "opt_inet.h" and "opt_inet6.h" and modify the IB
driver Makefiles to honor WITH/WITHOUT_INET/INET6/_SUPPORT options
to determine what should be enabled during a module build.
- Fix the mlxen(4) driver and the core IB code to compile without
if INET is disabled (including when both INET and INET6 are disabled).

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

- Don't use a separate set of rx queues for UDP, hash them into the same
set as TCP.
- Eliminate the fully linear non-scatter/gather rx path, there is no
harm in using arrays of clusters for both TCP and UDP.
- Implement support for enabling/disabling per-vlan priority pause and
queues via sysctl.

- Merge in OFED 1.5.3 from projects/ofed/head