libbinder_ndk: mv include_{apex,platform}

b/c this is no longer apex-specific

Bug: 136027762
Test: TH
Change-Id: I826cb83020234888f0eba09d64e0420a43f172eb
diff --git a/libs/binder/ndk/Android.bp b/libs/binder/ndk/Android.bp
index 1beacdf..574be7b 100644
--- a/libs/binder/ndk/Android.bp
+++ b/libs/binder/ndk/Android.bp
@@ -19,7 +19,7 @@
 
     export_include_dirs: [
         "include_ndk",
-        "include_apex",
+        "include_platform",
     ],
 
     cflags: [
@@ -80,6 +80,6 @@
     symbol_file: "libbinder_ndk.map.txt",
     export_include_dirs: [
         "include_ndk",
-        "include_apex",
+        "include_platform",
     ],
 }