fix(tree): correct some typos

found using codespell (https://github.com/codespell-project/codespell).

Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Change-Id: I1bfa797e3460adddeefa916bb68e22beddaf6373
diff --git a/include/lib/cpus/aarch64/generic.h b/include/lib/cpus/aarch64/generic.h
index 53df587..dd71554 100644
--- a/include/lib/cpus/aarch64/generic.h
+++ b/include/lib/cpus/aarch64/generic.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Arm Limited. All rights reserverd.
+ * Copyright (c) 2020, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */