Avoid compiling subfolders of fabric folder

Summary:
Only compile files under Fabric folder, without including subfolders

changelog: [internal] internal

Reviewed By: lunaleaps

Differential Revision: D39108916

fbshipit-source-id: 5390b78cd529e7256f4e755b6d88999546fa705b

ReactAndroid/src/main/jni/react/fabric/BUCK

@@ -7,7 +7,7 @@ rn_xplat_cxx_library(
     header_namespace = "",
     exported_headers = subdir_glob(
         [
-            ("", "**/*.h"),
+            ("", "*.h"),
         ],
         prefix = "react/fabric",
     ),