cpus offline themselves during a kdump procedure. This causes an
invalid cpu count determination during crash session initialization
from an ARM vmcore. The patch utilizes the cpu count found in the
cpu_active_map if it is greater than the count in the cpu_online_map.
In addition, the maximum NR_CPUS value for the ARM architecture has
been raised from 4 to 32.
(sdu.liu@huawei.com)