Merge tag 'intel_th-stm-for-greg-20190221' of git://git.kernel.org/pub/scm/linux...

Alexander writes:

stm class/intel_th: Updates for v5.1

These are:
  * 2 bugfixes in stm class
  * one bugfix in intel_th
  * a few minor cleanups

* tag 'intel_th-stm-for-greg-20190221' of git://git.kernel.org/pub/scm/linux/kernel/git/ash/stm:
  stm class: Prevent division by zero
  stm class: Fix an endless loop in channel allocation
  intel_th: Don't reference unassigned outputs
  intel_th: pti: Use sysfs_match_string() helper
  intel_th: Only create useful device nodes
  intel_th: Mark expected switch fall-throughs
  intel_th: Update ABI documentation