Merge branches 'pm-devfreq', 'pm-qos', 'pm-tools' and 'pm-docs'

Merge devfreq changes, PM QoS change, and power management tools and
documentation changes for v5.20-rc1:

 - Add new devfreq driver for Mediatek CCI (Cache Coherent
   Interconnect) (Johnson Wang).

 - Convert the Samsung Exynos SoC Bus bindings to DT schema of
   exynos-bus.c (Krzysztof Kozlowski).

 - Address kernel-doc warnings by adding the description for unused
   fucntion parameters in devfreq core (Mauro Carvalho Chehab).

 - Use NULL to pass a null pointer rather than zero according to the
   function propotype in imx-bus.c (Colin Ian King).

 - Print error message instead of error interger value in
   tegra30-devfreq.c (Dmitry Osipenko).

 - Add checks to prevent setting negative frequency QoS limits for
   CPUs (Shivnandan Kumar).

 - Update the pm-graph suite of utilities to the latest revision 5.9
   including multiple improvements (Todd Brandt).

 - Drop pme_interrupt reference from the PCI power management
   documentation (Mario Limonciello).

* pm-devfreq:
  PM / devfreq: tegra30: Add error message for devm_devfreq_add_device()
  PM / devfreq: imx-bus: use NULL to pass a null pointer rather than zero
  PM / devfreq: shut up kernel-doc warnings
  dt-bindings: interconnect: samsung,exynos-bus: convert to dtschema
  PM / devfreq: mediatek: Introduce MediaTek CCI devfreq driver
  dt-bindings: interconnect: Add MediaTek CCI dt-bindings

* pm-qos:
  PM: QoS: Add check to make sure CPU freq is non-negative

* pm-tools:
  pm-graph v5.9

* pm-docs:
  Documentation: PM: Drop pme_interrupt reference