s390/smp: increase maximum value of NR_CPUS to 512

With SMT we can have more than 256 CPUs. Let's make them available.

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