scsi: qla2xxx: Use nr_cpu_ids instead of NR_CPUS for qp_cpu_map allocation

Change the memory allocation for qp_cpu_map to use the actual number of
CPUs ('nr_cpu_ids') instead of the maximum possible CPUs ('NR_CPUS').
This saves memory on systems where the maximum CPU limit is much higher
than the active CPU count.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Link: https://patch.msgid.link/20260331053245.1839-1-lirongqing@baidu.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>