Add disk hotswap support to libata RESEND #2

Hey Jeff, all,

The following is my latest attempt at re-doing the hotswap patches for libata hotswapping. This has some positive upsides:

- The patches seem cleaner
- The patches seem more multi-purpose and adaptable for use across all controllers, not just the Promise ones.
- Jeff is more likely to accept them since most of his suggestions have been factored in.

There is also a downside:

- The patches haven't been tested at ALL since I don't have any hardware until September.

So, try at your own risk. Everything seems sane to me, however it is 3:00 AM here.

Jeff, these patches are designed against 2.6.13-rc3-mm1. As a result, they are meant to apply overtop of the sata_promise 'support PATA port' patch.

Please apply and try. And send me comments about how the patches are broken in weird scenarios.

Luke Kosewski