cpuset: add option to allow cpulist_parse() to fail

cpuset: add option to allow cpulist_parse() to fail

This is a preparation patch for chcpu. If a cpu should be added to
a cpu_set where the cpu doesn't fit into the cpu_set this got silently
ignored.
Since the cpu-list is user space provided it should be checked if cpus
are specified that are completely out of range of the system.
In order to do that add a parameter which specifies if cpulist_parse()
should fail if it parses a cpu-list with "impossible" cpus.
The current callers have been converted so they behave like before.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>