s390/cio: Consolidate inline assemblies and related data definitions

Replace the current semi-arbitrary distribution of inline assemblies:
 - Inline assemblies used by CIO go into ioasm.h
 - Data definitions used by inline assemblies go into cio.h

Beyond cleaning up the current structure this is also required for
use of tracepoints in inline assemblies introduced by a follow-on
patch.

Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Acked-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>