display-commonsys: Define a soong namespace

Legacy platforms use their own set of headers and libraries
within hardware/qcom-caf/msm[0-9]+/display, so we need to hide
this with a soong namespace

Change-Id: I7ee6b16d5d426c26cfdbfe3f0ae181a3b5e85173
diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..9515b25
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,2 @@
+soong_namespace {
+}