MFC r225869:

MFC r225869:
- Add special support for the MFI_CMD ioctl with MFI_CMD_STP command,
used by present MegaCLI version. It has some special meaning for the
first s/g list entry, while the main s/g list begins from the the second
entry, and those lists should remain separate after loading to the
busdma map.
 - Fix bug in 32bit ioctl compatibility shims when s/g list consists of
more then on element.

git-svn-id: svn://svn.freebsd.org/base/stable/8@225919 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f