Cleaned up AMD Au1200 IDE driver:

- converted to platform bus
- removed pci dependencies
- removed virt_to_phys/phys_to_virt calls
    
System now can root off of a disk.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/Documentation/mips/AU1xxx_IDE.README b/Documentation/mips/AU1xxx_IDE.README
new file mode 100644