MFC 239103:

MFC 239103:
Explicitly enable busmastering on PCI-PCI bridges.  Transactions initiated
on the secondary side of a bridge will not be propagated to the primary
bus unless this is enabled.  Busmastering is not enabled by default (we
have relied on firmware to set this bit to date).  The OS needs to set it
for any bridges not configured by system firmware.

git-svn-id: svn://svn.freebsd.org/base/stable/8@239918 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f