drm/radeon/kms/pm: rework power management

drm/radeon/kms/pm: rework power management

- Separate dynpm and profile based power management methods.  You can select the pm method
  by echoing the selected method ("dynpm" or "profile") to power_method in sysfs.
- Expose basic 4 profile in profile method
  "default" - default clocks
  "auto" - select between low and high based on ac/dc state
  "low" - DC, low power mode
  "high" - AC, performance mode
  The current base profile is "default", but it should switched to "auto" once we've tested
  on more systems.  Switching the state is a matter of echoing the requested profile to
  power_profile in sysfs.  The lowest power states are selected automatically when dpms turns
  the monitors off in all states but default.
- Remove dynamic fence-based reclocking for the moment.  We can revisit this later once we
  have basic pm in.
- Move pm init/fini to modesetting path.  pm is tightly coupled with display state.  Make sure
  display side is initialized before pm.
- Add pm suspend/resume functions to make sure pm state is properly reinitialized on resume.
- Remove dynpm module option.  It's now selectable via sysfs.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>