s390/zcrypt: make psmid unsigned long instead of long long

Since s390 kernel build does not support 32 bit build any
more there is no difference between long and long long.
So this patch reworks all occurrences of psmid (a 64 bit
value) to use unsigned long now.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>