Add AArch64 device Rust toolchain.

Bug: 141207434
Test: build example rust device module.
Change-Id: I0932a614942bf4a4d4b6c153fcc4fc79c7f202bd
diff --git a/Android.bp b/Android.bp
index 3ece110..b7f9691 100644
--- a/Android.bp
+++ b/Android.bp
@@ -333,6 +333,7 @@
         "soong-cc-config",
     ],
     srcs: [
+        "rust/config/arm64_device.go",
         "rust/config/global.go",
         "rust/config/toolchain.go",
         "rust/config/whitelist.go",