Fix ARM build for Tizen Common - disable NaCL for ARM arch

Change-Id: Ia617267fa2e7b96909271b20cb01a44a8e7035d6
Signed-off-by: Stephen Clymans <stephen.clymans@open.eurogiciel.org>
Merge pull request #2058 from eurogiciel-oss/XWALK-1673

Fix ARM build for Tizen Common