- typedef unsigned char byte; is finally gone. Everything using it should
   be just ported to u8 if I missed some place where it still gets used.

 - Next round of parameter parsing cleanups by Gerald Champagne.
   Adjusted a bit to harmonize with  hd.c.

 - Move IDE register bitfields declarations over from hdparm.h to
   ide.h.

 - Declare constants needed by hd.c directly there. Those are standard
   values not subject to change and we prefer a bit of code duplication
   in favour of making the two drivers independant from each other.

 - Move everything not ioctl related away from hdreg.h to ide.h.
   This header is in effect not private to the ATA code and should
   therefore not contain stuff only usefull there.