MFC r275624:
Add port routing support for Wildcat Point.

PR:		195793


git-svn-id: svn+ssh://svn.freebsd.org/base/stable/8@275787 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
MFC r275833:
The iret instruction may generate #np and #ss fault, besides #gp.
When returning to usermode, the handler for that exceptions is also
executed with wrong gs base.  Handle all three possible faults in the
same way, checking for iret fault, and performing full iret.


git-svn-id: svn+ssh://svn.freebsd.org/base/stable/8@275935 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f