staging: wlan-ng: Replace long int with long

Replace long int with long as int is unnecessary according to the
checkpatch.pl warning. K&R write, 'The word int can be omitted... and
typically is.'

Signed-off-by: Maya Nakamura <m.maya.nakamura@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>