realtime/librttest: get_numcpus() fix leak As pointed out on the mailing list this function has a memory leak, fixing it. Link: https://lore.kernel.org/ltp/[email protected]/ Fixes: 591c56b045 ("realtime/prio-preempt: take cpu isolation into consideration") Reviewed-by: Petr Vorel <[email protected]> Reviewed-by: Cyril Hrubis <[email protected]> Signed-off-by: Attila Fazekas <[email protected]>