Firstly, there is no need to have a double pointer here as we're only
walking the vmlist and not modifying it.
Secondly, for the same reason, we don't need a write lock but only a
read lock here, since the lock only protects the coherency of the list
nothing else.
Lastly, the reason for holding a lock is not what the comment says, so
let's remove that misleading piece of information.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
6ee723a657