s390/atomic: Consistent layering between atomic.h and atomic_ops.h

s390/atomic: Consistent layering between atomic.h and atomic_ops.h

With commit c8a91c285d8c ("s390/atomic: move remaining inline assemblies to
atomic_ops.h") all remaining atomic inline assemblies have been moved to
atomic_ops.h.

However the result is inconsistent: the functions in atomic_ops.h are
supposed to be used with integral types like int and long pointers, while
the functions in atomic.h work with atomic types.

This layering got violated with the named commit. Therefore adjust this
now, and also use consistent variable names in atomic_ops.h.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>