Add dirgroup for trusty genrule

Bug: 358302178
Test: m lk.elf.x86_64 lk.elf.arm64
Change-Id: Ibb22b9d67992bb3fa199cfc4ee4b615fbbb36680

Android.bp

diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..eca0ecb
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,5 @@
+dirgroup {
+    name: "trusty_dirgroup_trusty_device_x86_generic-x86_64",
+    dirs: ["."],
+    visibility: ["//trusty/vendor/google/aosp/scripts"],
+}