staging: ozwpan: Simplify app interface

Simplify the somewhat overcomplicated application interface; improves
readability and saves a bunch of lines.

Use designated struct initializers for clarity.

Signed-off-by: Christoph Jaeger <email@christophjaeger.info>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>