cpumask: Add cpu isolation support

Add bitmask and corresponding supporting functions for cpu isolation.

Change-Id: Ice1a9503666a2b720bdb324289ca55ceb33097cd
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
[rameezmustafa@codeaurora.org: Port to msm-4.9]
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>
Signed-off-by: Raghavendra Rao Ananta <rananta@codeaurora.org>