On systems where the calculated cpu shares results in a value above the
max value in linux, containers getting that value are unable to start.
This occur on systems with 300+ cpu cores, and where containers are
given such a value.
This issue was fixed for the pod and qos control groups in the similar
cm.MilliCPUToShares that also has tests verifying the behavior. Since
this code already has an dependency on kubelet/cm, lets reuse that code
instead.
