staging/rtl8192u: indent with tabs, not spaces

Converted staging/rtl8187se to use tabs instead of spaces for
indentation to fix the checkpatch error "code indent should use tabs
where possible".
Signed-off-by: Sebastian Hahn <snsehahn@cip.cs.fau.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>