s390/sigp: use sigp order code defines in assembly code

Use sigp order code defines in assembly code as well.
With this change all places that use sigp constants should
have been converted to use self describing defines instead
of directly using constants.

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