MFC r273135 and r273867:

MFC r273135 and r273867:
Update the OFED Linux compatibility layer and
Mellanox hardware driver(s):

- Properly name an inclusion guard.
- Fix compile warnings regarding unsigned enums.
- Fix compile warning regarding unused variable.
- Add two new sysctl nodes.
- Remove all empty linux header files.
- Make an error printout more verbose.
- Use "mod_delayed_work()" instead of
  cancelling and starting a timeout.
- Implement more Linux scatterlist
  functions.
- Don't forget to add "options OFED" to
  the kernel configuration file before
  using infiniband.

Sponsored by:	Mellanox Technologies

git-svn-id: svn://svn.freebsd.org/base/stable/9@273868 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f