drm/i915: Assign everywhere the always-on power well ID

Power well IDs are used for lookup so they must be unique. To ensure
this assign the always-on power well ID everywhere where it's missing.
This didn't cause a problem so far, since we didn't need to look up
power wells that happened to share their IDs.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1499352040-8819-4-git-send-email-imre.deak@intel.com


Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>