Anaconda (or libata?) device detection order

[Alan Cox]

> I do not think that there is any way for anaconda, given the constraints 
> of libata and the BIOS, to determine if the first drive offered is PATA.

In theory you can map BIOS drives to PCI devices using EDD 3.0 tables and
then use word 93 of the identify data to map the devices to PATA v SATA.

In practice EDD tables seem to be pretty good but various devices get
word 93 wrong - notably cruddy ATAPI devices.

Our current order is basically

- link order for compiled in drivers (if any), which is fairly undefined
but does put acpi, generic, legacy last

- module load order otherwise

For multiple devices off the same module it is then defined by the PCI
bus ordering of devices which depends on the PCI scan order.

The order modules get loaded is from userspace