Spelling fixes

Spelling errors found using github.com/lucasdemarchi/codespell
A tool to fix common misspellings.
This tool is licensed under GNU General Public License, version 2.

Change-Id: I2ca3fd16d7cc84fdce63089b47fefb8f128894fd
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/image_verify.hpp b/image_verify.hpp
index f2387c7..c40713c 100644
--- a/image_verify.hpp
+++ b/image_verify.hpp
@@ -151,7 +151,7 @@
      *        of image specific publickey file and manifest file
      *        using the available public keys and hash functions
      *        in the system.
-     *        Refer code-update documenation for more details.
+     *        Refer code-update documentation for more details.
      */
     bool systemLevelVerify();