[Kernel] Added support for writing/reading GPD files

This breaks settings in games that are using them and savefiles in games that use settings to store progress

src/xenia/vfs/devices/null_entry.cc

@@ -51,5 +51,7 @@ X_STATUS NullEntry::Open(uint32_t desired_access, File** out_file) {
   return X_STATUS_SUCCESS;
 }
 
+bool NullEntry::DeleteEntryInternal(Entry* entry) { return false; }
+
 }  // namespace vfs
 }  // namespace xe