Make crate vendor_available

Bug: 195310053
Test: build, TreeHugger
Change-Id: I466a7cf609a3c945a56d3f3fac99cbc04cb4dc9b
diff --git a/trusty/libtrusty-rs/Android.bp b/trusty/libtrusty-rs/Android.bp
index bc1dcf6..4fc162b 100644
--- a/trusty/libtrusty-rs/Android.bp
+++ b/trusty/libtrusty-rs/Android.bp
@@ -19,6 +19,7 @@
 rust_library {
     name: "libtrusty-rs",
     crate_name: "trusty",
+    vendor_available: true,
     srcs: [
         "src/lib.rs"
     ],