MFC r271308:
Make ZVOL writes in device mode support IO_SYNC flag.
MFC r271309:
Improve cache control support, including DPO/FUA flags and the mode page.

At this moment it works only for files and ZVOLs in device mode since BIOs
have no respective respective cache control flags (DPO/FUA).
MFC r271311:
Add support for Mode Page Policy (0x87) VPD page.
MFC r271316: Report that DPO and FUA bits are supported after r271311.
MFC r271352: Fix minor buffer overflow reported by Coverity.
MFC r271353: Fix memory leak on error, reported by Coverity.
MFC r271354: Fix couple off-by-one range check errors, reported by Coverity.
MFC r271358: Fix array overrun, reported by Coverity.