staging:rtl8192u: Remove unused Zebra4 definitions - Style

Remove the unused 'Zebra4' definitions. These definitions fail the
checkpatch CamelCase naming test, rather then rename as they are unused
definitions they have simply been removed. This is a coding style
change which should not impact runtime code execution.

Signed-off-by: John Whitmore <johnfwhitmore@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>