cpuset: convert to new cpumask API

This patchset converts cpuset to use new cpumask API, and thus
remove on stack cpumask_t to reduce stack usage.

Before:
 # cat kernel/cpuset.c include/linux/cpuset.h | grep -c cpumask_t
 21
After:
 # cat kernel/cpuset.c include/linux/cpuset.h | grep -c cpumask_t
 0

The patchset is based on mmotm 2008-12-30-16-05.

[PATCH 1/6] cpuset: remove on stack cpumask_t in cpuset_sprintf_cpulist()
[PATCH 2/6] cpuset: remove on stack cpumask_t in cpuset_can_attach()
[PATCH 3/6] cpuset: convert cpuset_attach() to use cpumask_var_t
[PATCH 4/6] cpuset: don't allocate trial cpuset on stack
[PATCH 5/6] cpuset: convert cpuset->cpus_allowed to cpumask_var_t
[PATCH 6/6] cpuset: remove remaining pointers to cpumask_t
---
 include/linux/cpuset.h   |   10 +
 kernel/cpuset.c          |  279 ++++++++++++++++++++++++++++-------------------
 3 files changed, 174 insertions(+), 115 deletions(-)