mm: fix off-by-one bug in print_nodes_state()

mm: fix off-by-one bug in print_nodes_state()

/sys/devices/system/node/{online,possible} outputs a garbage byte because
print_nodes_state() returns content size + 1.  To fix the bug, the patch
changes the use of cpuset_sprintf_cpulist to follow the use at other
places, which is clearer and safer.

This bug was introduced since v2.6.24 (bde631a51876f23e9).

Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>