Add arch specific dev_archdata to struct device

Adds an arch specific struct dev_arch to struct device. This enables
architecture to add specific fields to every device in the system, like
DMA operation pointers, NUMA node ID, firmware specific data, etc...

Signed-off-by: Benjamin Herrenschmidt
Acked-by: Andi Kleen
Acked-By: David Howells
Signed-off-by: Greg Kroah-Hartman