l1 position controller: make sure that a NAN roll setpoint does not keep the roll setpoint state at NAN forever
l1 position controller: make sure that a NAN roll setpoint
does not keep the roll setpoint state at NAN forever

Signed-off-by: Roman <019237760eff64d50a7eec108f84e3d8840aac17@gmail.com>

PX4/ecl,PX4/ecl,PX4/ecl,PX4/ecl,PX4/ecl