s390/smp: remove redundant check

condition code "status stored" for sigp sense running always implies
that only the "not running" status bit is set. Therefore no need to
check if it is set.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>