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: I2a2cf8b85dc24b4f109e05ed176d1e24bc8717cc
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/slp.hpp b/slp.hpp
index d0df089..fa8aad6 100644
--- a/slp.hpp
+++ b/slp.hpp
@@ -121,7 +121,7 @@
 
 
 /*
- * @struct Messsage
+ * @struct Message
  *
  * This will denote the slp Message.
  */