This is a leftover of the time where the memory size was stored as
64 bit value. Now it is stored as 32 bit value, so no need to truncate.

R=ahaas@chromium.org

Change-Id: I44a1505ebd564aee53e4c9a7168738fcb855264b
Reviewed-on: https://chromium-review.googlesource.com/1034883Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52905}