FileSys: Append the requested path to the filesystem base path in DeleteFile.

We were trying to delete things in the current directory instead of the actual filesystem directory. This may fix some savedata issues in some games.

src/core/file_sys/disk_filesystem.cpp

@@ -58,11 +58,13 @@ ResultVal<std::unique_ptr<StorageBackend>> Disk_FileSystem::OpenFile(const std::
 }
 
 ResultCode Disk_FileSystem::DeleteFile(const std::string& path) const {
-    if (!FileUtil::Exists(path)) {
+    std::string full_path = base_directory + path;
+
+    if (!FileUtil::Exists(full_path)) {
         return ERROR_PATH_NOT_FOUND;
     }
 
-    FileUtil::Delete(path);
+    FileUtil::Delete(full_path);
 
     return RESULT_SUCCESS;
 }