MFC r329771: MFV r329770: 9035 zfs: this statement may fall through

illumos/illumos-gate@46ac8fdfc5a1f9d8240c79a6ae5b2889cbe83553

Reviewed by: Yuri Pankov <yuripv@yuripv.net>
Reviewed by: Andy Fiddaman <omnios@citrus-it.co.uk>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Toomas Soome <tsoome@me.com>

MFC r324163: MFV r323530,r323533,r323534: 7431 ZFS Channel Programs, and followups

Also MFC-ed are the following fixes:
- r324164 Add several new files to the files enabled by ZFS kernel option
- r324178 unbreak kernel builds on sparc64 and powerpc
- r324194 fix incorrect use of getzfsvfs_impl in r324163
- r324292 really unbreak kernel builds on sparc64 and powerpc64