sched: Limit setaffinity with CPU_HOTPLUG

Some applications do not count CPU's correctly and make bad
decisions on systems with hotplugged CPU's.

Limit app's ability to use setaffinity based on CONFIG_CPU_HOTPLUG.

Signed-off-by: Chris Fries <C.Fries@motorola.com>
Reviewed-on: http://gerrit.pcs.mot.com/528092
SLT-Approved: Gerrit Code Review <gerrit-blurdev@motorola.com>
Tested-by: Jira Key <jirakey@motorola.com>
Reviewed-by: Christopher Fries <qcf001@motorola.com>
Reviewed-by: Jeffrey Carlyle <jeff.carlyle@motorola.com>
Reviewed-by: Klocwork kwcheck <klocwork-kwcheck@sourceforge.mot.com>
Reviewed-by: Igor Kovalenko <cik009@motorola.com>
Submit-Approved: Jira Key <jirakey@motorola.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>