ata-scsi driver update

[Jeff Garzik]

maintenance update, nothing terribly new or exciting.  mostly error 
handling improvements and cleanups (and some bug fixes just for fun).

GNU diff, versus 2.4.21 release:
ftp://ftp.kernel.org/pub/linux/kernel/people/jgarzik/patchkits/2.4/2.4.21-atascsi1.patch.bz2

BK repos:
bk://kernel.bkbits.net/jgarzik/atascsi-2.[45]

The 2.5 repo is a bit out of date WRT the latest scsi api, but the 
ata-scsi driver itself is 100% in sync with its 2.4 counterpart.  (due 
to the large number of changes in 2.5 scsi, the 2.5 driver is a fork of 
the 2.4 driver)

detailed changes:
* add autogenerated docbook docs
* add atapi (ifdef'd out, due to lack of err handling)
* better ata probing, including better err handling during probe
* more piix pci ids.  bump up ich5 sata max speed to udma6.
* beginnings of SYNCHRONIZE CACHE support for ATA drives
* better SCSI emulation for ATA drives
* cleanups, simplifications, minor bug fixes
* a huge search-n-replace job, s/ata_host/ata_port/

A couple new host drivers coming next, along with atapi error handling...