Add libnetd_utils_headers cc_library_headers

There is a module that specifies libnetdutils/include from include_dirs
which is not recommended.
Using the cc_library_headers makes it easy to move
frameworks/libs/net to packages/modules/Connectivity.

Bug: 296014682
Test: m

Change-Id: Ia52ede9787009102ebf626fcb3b337511b0a809f
diff --git a/staticlibs/netd/libnetdutils/Android.bp b/staticlibs/netd/libnetdutils/Android.bp
index 08d5412..3169033 100644
--- a/staticlibs/netd/libnetdutils/Android.bp
+++ b/staticlibs/netd/libnetdutils/Android.bp
@@ -66,3 +66,8 @@
         "libbase",
     ],
 }
+
+cc_library_headers {
+    name: "libnetd_utils_headers",
+    export_include_dirs: ["include"],
+}