This patch adds support for executing multiple concurrent requests on
different devices on the same AHCI controller. The libdriver library
has been extended to include a generic multithreading interface, and
the AHCI driver has been extended to make use of this interface.
The original version of this code has been written by Arne Welzel.
- check the DF status flag after each command
- increase I/O timeout from 15 to 30 seconds
- share some code between ATA and ATAPI after all
- produce more accurate errors on DIOCEJECT
- rename AHCI_ID_SIZE to the more appropriate ATA_ID_SIZE
- rearrange ahci.h in a now more sensible way
