artik710s: add mfg firmware binaries path
artik710s: add mfg firmware binaries path

This patch adds mfg firmware path for artik hwtest image.

Change-Id: Iccf9ac9ce5dfc77b6d73e6e3d64a1e16c3cf6b56
Signed-off-by: Chanho Park <8ec285a53e21b773fd914e03c50e1b6431bc9aa8@samsung.com>

SamsungARTIK/build-artik