PNP: add pnp_resource_type() internal interface

Given a struct resource, this returns the type (IO, MEM, IRQ, DMA).

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>