s390/cmpxchg: use register pair instead of register asm
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
authored by Heiko Carstens and committed by Vasily Gorbik 4 years ago 79ee201e 2bd67038