Added CONTROL device that only does user-ioctl and nothing else;
Added protection so user-ioctl requires write access;
Clean up scsiconf.h a little. It needs more work.
flags parameter to all xxstart routines so that the correct information can
be passed down into the device specific routines. This is needed to ensure
that ccb/scb allocation routines don't hang.
Submitted by: John Dyson