cpumask: fix checking valid cpu range

The range of valid CPUs is [0, nr_cpu_ids). Some cpumask functions are
passed with a shifted CPU index, and for them, the valid range is
[-1, nr_cpu_ids-1). Currently for those functions, we check the index
against [-1, nr_cpu_ids), which is wrong.

Signed-off-by: Yury Norov <yury.norov@gmail.com>