PNP: make pnp_add_id() internal to PNP core

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: Bjorn Helgaas <bjorn.helgaas@hp.com>
Acked-By: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/pnp/pnpacpi/core.c b/drivers/pnp/pnpacpi/core.c
index 53f9106..4807d76 100644
--- a/drivers/pnp/pnpacpi/core.c
+++ b/drivers/pnp/pnpacpi/core.c
@@ -25,6 +25,7 @@
 #include <acpi/acpi_bus.h>
 #include <acpi/actypes.h>
 
+#include "../base.h"
 #include "pnpacpi.h"
 
 static int num = 0;