drm/i915: Fix memleak in runtime wakeref tracking

drm/i915: Fix memleak in runtime wakeref tracking

If we untrack wakerefs, the actual count may reach zero.
However the krealloced owners array is still there and
needs to be taken care of. Free the owners unconditionally
to fix the leak.

Fixes: c7a48516c612 ("drm/i915: Track all held rpm wakerefs")
Reported-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Cc: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190701104442.9319-1-mika.kuoppala@linux.intel.com
(cherry picked from commit c5f846eed2a1856b78e988eeef08215c70598ecd)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>