PNP: convert to using pnp_dbg()

pnp_dbg() is equivalent to dev_dbg() except that we can turn it
on at boot-time with the "pnp.debug" kernel parameter, so we don't
have to build a new kernel image.

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