tizen: Add iotivity namespace for headers

tizen: Add iotivity namespace for headers

Currently symlink to parent folder,
 this way it's aligned to yocto recipe.

In longer term it would be nice to rely on scons install rules.

Change-Id: Ie8067c13302ccf92936d599bb4f6b3740d3cf009
Bug: https://jira.iotivity.org/browse/IOT-524
Signed-off-by: Philippe Coval <philippe.coval@osg.samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/12149
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Dave Thaler <dthaler@microsoft.com>
Reviewed-by: Ziran Sun <ziran.sun@samsung.com>
(cherry picked from commit 5a494b98d65b2950a9331ec77b03ce429ba64cde)
Reviewed-on: https://gerrit.iotivity.org/gerrit/12485