s390: remove 31 bit syscalls

Remove the 31 bit syscalls from the syscall table. This is a separate patch
just in case I screwed something up so it can be easily reverted.
However the conversion was done with a script, so everything should be ok.

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