Missing parens.

fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=30718Reported-by: NDave Gilbert <freedesktop@treblig.org>
Signed-off-by: NAlex Deucher <alexdeucher@gmail.com>
Reviewed-by: NMatt Turner <mattst88@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>