Don't link with libbinder itself just for the headers

By linking with libbinder.so, it ends up being an actual dependency
for anything that links with android.hidl.token@1.0-utils, which
results in it being copied into APEX files when it shouldn't be.
Use libbinder_headers instead.

Test: build
Change-Id: Ied5a108e4ae8f862fae42a81594d6f0e414a4685
diff --git a/transport/token/1.0/utils/Android.bp b/transport/token/1.0/utils/Android.bp
index d706cf6..5a8d51c 100644
--- a/transport/token/1.0/utils/Android.bp
+++ b/transport/token/1.0/utils/Android.bp
@@ -25,16 +25,22 @@
         "HybridInterface.cpp",
     ],
 
+    header_libs: [
+        "libbinder_headers",
+    ],
+
     shared_libs: [
         "libutils",
-        "libbinder",
         "liblog",
         "libhidlbase",
         "android.hidl.token@1.0",
     ],
 
+    export_header_lib_headers: [
+        "libbinder_headers",
+    ],
+
     export_shared_lib_headers: [
-        "libbinder",
         "libhidlbase",
     ],