MFC r254132:
  Add empty zones for Shared Address Space (RFC 6598)

Approved by:  delphij (mentor)
Sponsored by: DK Hostmaster A/S
Merge r254263:

Update PCI drivers to no longer look at the MEMIO-enabled bit in the PCI
command register.  The lazy BAR allocation code in FreeBSD sometimes
disables this bit when it detects a range conflict, and will re-enable
it on demand when a driver allocates the BAR.  Thus, the bit is no longer
a reliable indication of capability, and should not be checked.  This
results in the elimination of a lot of code from drivers, and also gives
the opportunity to simplify a lot of drivers to use a helper API to set
the busmaster enable bit.

This changes fixes some recent reports of disk controllers and their
associated drives/enclosures disappearing during boot.

Candidate for 9.2

Submitted by:	jhb
Reviewed by:	jfv, marius, adrian, achim
MFC r254020:
Add a missing module version declaration to if_tun(4).
MFC r254017:
Fill in the description fields for M_FICT_PAGES.
MFC r253850:
Properly print arguments to vfork(2) and rfork(2).
Merge remote-tracking branch 'upstream-github/stable/9' into stable/9