Squashed 'external/devlib/' changes from 8871fe3c..8512f116

8512f116 trace: Add DmesgCollector
be8b87d5 module/sched: Fix/simplify procfs packing behaviour
d76c2d63 module/sched: Make get_capacities() work with hotplugged CPUs
8bfa0502 module/sched: SchedProcFSData: Don't assume SD name is always present

git-subtree-dir: external/devlib
git-subtree-split: 8512f116fc5de214fd73cacf474b3109323a5754