otautil: Android.mk -> Android.bp

Test: flash and boot recovery on internal angler
Change-Id: Id8845b4b422d0078b251333eb6d30ce14771ef10
diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..f919ebc
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,3 @@
+subdirs = [
+    "otautil",
+]