Fix bug that missing the self argument in get_power_state_controller()

A trivial bug that missing the self argument.

BUG=chrome-os-partner:18541
TEST=None, trivial fix

Change-Id: Ic051af234b50180c95e9ecbe2326ccc57c9887b8
Reviewed-on: https://gerrit.chromium.org/gerrit/47228
Reviewed-by: Vic Yang <victoryang@chromium.org>
Commit-Queue: Tom Wai-Hong Tam <waihong@chromium.org>
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>
1 file changed