Add hardware/ti/am57x Soong namespace.

Change-Id: I20c13e85463b302af20337a133c0676a2cc63b78
Fixes: 123701160
Test: Manual build + check OUT_DIR contents.
diff --git a/device.mk b/device.mk
index 3d21e6a..b766b4e 100644
--- a/device.mk
+++ b/device.mk
@@ -14,6 +14,9 @@
 # limitations under the License.
 #
 
+PRODUCT_SOONG_NAMESPACES += \
+	hardware/ti/am57x
+
 # Adjust the dalvik heap to be appropriate for a tablet.
 $(call inherit-product, frameworks/native/build/tablet-7in-xhdpi-2048-dalvik-heap.mk)