MFC DMAR busdma implementation.

MFC DMAR busdma implementation.

MFC r257251:
Import the driver for VT-d DMAR hardware.  Implement the busdma(9) using DMARs.

MFC r257512:
Add support for queued invalidation.

MFC miscellaneous follow-ups to r257251.

MFC r257266:
Remove redundand assignment to error variable and check for its value.

MFC r257308:
Remove redundand declaration.

MFC r257511:
Return BUS_PROBE_NOWILDCARD from the DMAR probe method.

MFC r257860,r257896,r257900,r257902,r257903 (by dim):
Fixes for gcc compilation.

git-svn-id: svn://svn.freebsd.org/base/stable/10@259512 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f