device: Fix dev_dbg_once macro

There is a copy/paste typo in the dev_dbg_once macro.

It uses dev_info instead of dev_dbg, so use the correct
function instead.

Signed-off-by: Joe Perches <joe@perches.com>
Noticed-by: Marc Finet <m.dreadlock@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>