irdma(4): Add code for compilation on stable/13 branch

Current content of the irdma(4) driver consists only of code that is
compilable on current 14-CURRENT branch which makes it impossible to
merge into stable/13 branch because of missing dependencies in the ofed
tree.

This patch adds missing code that allows for merging into stable branch.
Once it is there, code relating only to version 14 or higher should be
removed.

Signed-off-by: Eric Joyner <erj@FreeBSD.org>

Reviewed by: erj@
MFC after: 1 day
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D38170