Fix ARM build for Tizen Common

BUG : https://crosswalk-project.org/jira/browse/XWALK-1673

Better comment for explanation of the problem.

Change-Id: Ib66d841dc17d386c18b5c04aac6c90fa8f03fa4f
Signed-off-by: Stephen Clymans <stephen.clymans@open.eurogiciel.org>