Expose binder security context to rust binder services

This patch exposes AIBinder_setRequestingSid and AIBinder_getCallingSid
to binder services written in Rust. This is required by services to
effectively enforce SEPolicy because relying only on the caller's PID is
racy.

Bug: 165070170
Test: atest rustBinderTest
Change-Id: Iae25d4fedded7d133354ba4c82527f33e5d5e1ce
diff --git a/libs/binder/rust/sys/BinderBindings.h b/libs/binder/rust/sys/BinderBindings.h
index c7a06d9..303f4a5 100644
--- a/libs/binder/rust/sys/BinderBindings.h
+++ b/libs/binder/rust/sys/BinderBindings.h
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#include <android/binder_context.h>
 #include <android/binder_ibinder.h>
 #include <android/binder_manager.h>
 #include <android/binder_parcel.h>