Update platform namespace name

Platform namespace has been renamed as 'system' from linkerconfig
generator. To meet this requirement, libnativeloader should search for
namespace 'system' rather than namespace 'platform'.

Bug: 147987608
Test: m -j passed
Test: atest libnativeloader_test passed
Change-Id: I23d865ac71a80619f291eb9ae0761a2cad5df352
diff --git a/libnativeloader/native_loader_namespace.h b/libnativeloader/native_loader_namespace.h
index d07c431..ee84f61 100644
--- a/libnativeloader/native_loader_namespace.h
+++ b/libnativeloader/native_loader_namespace.h
@@ -60,7 +60,7 @@
 
   static Result<NativeLoaderNamespace> GetExportedNamespace(const std::string& name,
                                                             bool is_bridged);
-  static Result<NativeLoaderNamespace> GetPlatformNamespace(bool is_bridged);
+  static Result<NativeLoaderNamespace> GetSystemNamespace(bool is_bridged);
 
  private:
   explicit NativeLoaderNamespace(const std::string& name, android_namespace_t* ns)