- Make for less terse error messages in ide-tape.c.

- Replaced all timecomparisions done by hand with all the proper timer_after()
   commands.

- Remove the drive niec1 mechanisms alltogether. There are several reasons for
   this:

   1. The code implementing it is nonintelliglible and therefore propably
   broken.

   2. If we have to invent somethig about sceduling drive IO, it should be done
   on the BIO level.

   3. We may in fact interleave with the IO sceduling on the upper layers and
   the results of two overlapping signal filters overlapped with each other can
   be disasterous to the overall throughput. (In fact they *are* most of the
   time.)

   4. It was not working if you had intermixed modes on different drives
   DMA versus PIO.

   5. Our goal is to have a driver which is able to share the badwidth
   properly and shouldn't needing this kind of "tuning".

- Remove unused nice2 from disk struct.

- Rename channel member of ata_channel to unit and device to dev to
   just prevent wrong interpretations. This prevents constructs like
   channel->channel...