[ARM] BAST/VR1000: Move to using ata_platform (libata)

Use the pata_platform driver to provide the IDE port
drivers on the Simntec BAST and Thorcom VR1000 machines
as a precursor to removing drivers/ide/arm/bast-ide.c

This will mean that the system will need SCSI and SCSI disc
support as a minimum, and any references to hdX will be
changed to sdX.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>