2.4.x libata fixes (mostly)

Description reproduced from 2.6 version at http://marc.theaimsgroup.com/?l=linux-kernel&m=110918919831955&w=2:

This BK push includes additional hardware support, but that's only because it's (a) obviously low impact and (b) it was in the queue.

Far more important are:

1) API additions, to fix a severe bug: advanced drivers such as AHCI were directly bitbanging --non-existent-- PCI IDE registers, causing an oops, because of function calls buried deep within libata.

Solution: add the necessary hooks that should have existed all along, for this functionality.

2) Fix stomping on active devices, if pci_request_regions() fails. It is rather more urgent for libata than other situations, since we must deal with PCI devices that secretly export ISA device regions (legacy IDE 0x1f0, 0x170).

3) Fix command queue leak, if SCSI->ATA translation fails.