PNP: remove old CONFIG_PNP_DEBUG option

CONFIG_PNP_DEBUG is no longer used to turn on dev_dbg() in PNP,
since we have pnp_dbg() which can be enabled at boot-time, so
this patch removes the config option.

Note that pnp_dock_event() checks "#ifdef DEBUG".  But there's
never been a clear path for enabling that via configgery.  It
happened that CONFIG_PNP_DEBUG enabled it after 1bd17e63,
but that was accidental and only in 2.6.26.

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>