usbip: stub: stop printing kernel pointer addresses in messages

commit 248a22044366f588d46754c54dfe29ffe4f8b4df upstream.

Remove and/or change debug, info. and error messages to not print
kernel pointer addresses.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>