tizen: Guess TARGET_ARCH from gbs param

tizen: Guess TARGET_ARCH from gbs param

I noticed that previously arm binary where built into out/x86
Even if this is not harmful, It's better to rely on gbs's %{_arch}.

Change-Id: I1968c8d3c0705c536a2b055090ea142100f91bc2
Signed-off-by: Philippe Coval <philippe.coval@osg.samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/20309
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Ziran Sun <ziran.sun@samsung.com>
(cherry picked from commit 5c26449ec8c725cdc8f4f7a99f6ac9c664400760)
Reviewed-on: https://gerrit.iotivity.org/gerrit/21003
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>
Reviewed-by: George Nash <george.nash@intel.com>