selftests/futex: Add headers to makefile dependencies

The futex makefile did not contain dependencies for all headers, so if
we make changes to logging.h rebuild will not happen. Add headers to
fix it up.

Signed-off-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>