pass-through linux ioctl for mfi(4)

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

Hello,
the attached patch adds a pass-through ioctl interface, with the
necessery linux compat code, for mfi(4). This allows to run the
linux binary of the MegaCLI tool provided by LSI logic.
Adding support for the FreeBSD binaries should be easy, once
the COMPAT_FREEBSD is updated to run recent binaries.
(I found that running a 9265-8i without MegaCLI has lots of
limitations, e.g. you have to reboot and enter firmware to start
reconstruction after a disk remplacement).

One problem is that the key conflicts with the ossaudio ioctl.
What I've done is that I explicitely test for the mfi ioctls in
linux_ioctl.c. Does anyone see a better way of handling this ?
More generaly, does anyone have any comments about this code ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--