pnp_add_id() doesn't need to be exposed outside the PNP core, so
move the declaration to an internal header file.
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Acked-By: NRene Herman <rene.herman@gmail.com>
Signed-off-by: NLen Brown <len.brown@intel.com>