s390: remove non existent reference to GENERIC_KERNEL_THREAD

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
1 file changed