Add mesa3d Soong namespace

cherry-picked from upstream device/linaro/dragonboard project.

mesa3d is starting to migrate to Soong.

Bug: 122332854
Test: treehugger
Change-Id: I25c23e7cfca8e2662524d9e2e958cd6873669101
Signed-off-by: Amit Pundir <pundiramit@gmail.com>
diff --git a/device-common.mk b/device-common.mk
index eccc912..35b18fe 100644
--- a/device-common.mk
+++ b/device-common.mk
@@ -159,3 +159,5 @@
 
 # Copy firmware files
 $(call inherit-product-if-exists, $(LOCAL_PATH)/firmware/device.mk)
+
+PRODUCT_SOONG_NAMESPACES += external/mesa3d