Fix uninitialised variable and printk format bug from previous commit

Also make unsed functions inline to suppress warnings.
Move and rename ia32 IDE driver to generic ATA driver

In preparation for making it a PCI-ATA driver with vendor-specific
extenstion functionality.
ATA: fixup whitespace and naming issues

IDE is the name of a cable, ATA is the name of the host interface.
Export pcidev config space read/write functions
Implement PCI class driver infrastructure

Allow PCI drivers to register based on mask/val compare of the class,
subclass, programming interface and revision bits using an initcall-like
infrastructure.