MFC r264091

MFC r264091

   Correct a PCI enumeration bug introduced in r264011

   Ensure that first_func is set to 0 on every iteration of the PCI slot
   enumeration loop after the first.  There is a continue statement that would
   cause first_func to stay at 1 any PCI device where slot 0 has no functions
   until we find a slot that does have a function.  This would cause us to
   not enumerate the first PCI function on the device.

   Credit to markj@ for spotting the bug.

   X-MFC-With: r264011

git-svn-id: svn://svn.freebsd.org/base/stable/10@279471 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f