- Move ide_fixstring() from ide.c to probe.c, since this is the place, where it's
   most used.

 - Remove GET_STAT() - it's not used any longer.

 - Remove last parameter of ide_error. Rename it to ata_error().

 - Don't use ide_fixstring in qd65xx.c host chip driver. The model name is
   already fixed in probe.c.

 - Invent ata_irq_enable() for the handling of the trice nIEN bit of the
   control register.  Consistently use ch->intrproc method every time we toggle
   this bit.  This simply wasn't the case before!

 - Disable interrupts on a previous channel only when we share them indeed.

 - Eliminate simple drive command handling function drive_cmd.

 - Simplify the ioctl handler. Move it to ioctl, since that's the only place
   where it's actually used.