PNP: add CONFIG_PNP_DEBUG_MESSAGES and pnp_dbg()

This adds the core function pnp_dbg() and a new config option to
enable it.

The PNP core debugging messages can be enabled at boot-time with the
"pnp.debug" kernel parameter.

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>
diff --git a/drivers/pnp/Kconfig b/drivers/pnp/Kconfig
index 821933f..8a3237f 100644
--- a/drivers/pnp/Kconfig
+++ b/drivers/pnp/Kconfig
@@ -20,6 +20,20 @@
 
 	  If unsure, say Y.
 
+config PNP_DEBUG_MESSAGES
+	default y
+	bool "PNP debugging messages"
+	depends on PNP
+	help
+	  Say Y here if you want the PNP layer to be able to produce debugging
+	  messages if needed.  The messages can be enabled at boot-time with
+	  the pnp.debug kernel parameter.
+
+	  This option allows you to save a bit of space if you do not want
+	  the messages to even be built into the kernel.
+
+	  If you have any doubts about this, say Y here.
+
 if PNP
 
 config PNP_DEBUG