PNP: convert the last few pnp_info() uses to printk()

There are only a few remaining uses of pnp_info(), so I just
converted them to printk and removed the pnp_err(), pnp_info(),
pnp_warn(), and pnp_dbg() wrappers.

I also removed a couple debug messages that don't seem useful any
more ("driver registered", "driver unregistered", "driver attached").

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>