Fix minor bug in dispatch table initialization order.

Other minor changes:
 * document assignment that relies on _Atomic assignments to use
   atomic_store.
 * consistently use atomic_store when assigning to atomics.
 * remove incorrect comment.

Test: m
Test: flash & boot sailfish

Change-Id: I4789c08f7ac28a2de8d6925d03af354514bfd9d7