buildroot

package/systemd: remove unnecessary make opts

These flags were originally needed to support uClibc in earlier releases.

Signed-off-by: Gabe Evans <gabe@hashrabbit.co>
Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>