qemu: Use the CPU index in capabilities to map NUMA node to cpu list.

qemu: Use the CPU index in capabilities to map NUMA node to cpu list.

On some of the NUMA platforms, the CPU index in each NUMA node
grows non-consecutive. While on other platforms, it can be inconsecutive,
E.g.

% numactl --hardware
available: 4 nodes (0-3)
node 0 cpus: 0 4 8 12 16 20 24 28
node 0 size: 131058 MB
node 0 free: 86531 MB
node 1 cpus: 1 5 9 13 17 21 25 29
node 1 size: 131072 MB
node 1 free: 127070 MB
node 2 cpus: 2 6 10 14 18 22 26 30
node 2 size: 131072 MB
node 2 free: 127758 MB
node 3 cpus: 3 7 11 15 19 23 27 31
node 3 size: 131072 MB
node 3 free: 127226 MB
node distances:
node   0   1   2   3
  0:  10  20  20  20
  1:  20  10  20  20
  2:  20  20  10  20
  3:  20  20  20  10

This patch is to fix the problem by using the CPU index in
caps->host.numaCell[i]->cpus[i] to set the bitmask instead of
assuming the CPU index of the NUMA nodes are always sequential.