Fix include path for message.hpp

This resolves the below compilation error related to the missing
message.hpp file during full build.

'''
usr/include/ipmid/message/pack.hpp:18:10: fatal error: include/ipmid/message.hpp:
No such file or directory
'''

Updated the include directive to use the correct relative path for
message.hpp

Change-Id: Ice8a60a7030448ce75f0fa255ded9117beb1a71f
Signed-off-by: Jayanth Othayoth <ojayanth@gmail.com>
diff --git a/include/ipmid/message/pack.hpp b/include/ipmid/message/pack.hpp
index 9225d60..724bffc 100644
--- a/include/ipmid/message/pack.hpp
+++ b/include/ipmid/message/pack.hpp
@@ -15,7 +15,7 @@
  */
 #pragma once
 
-#include <include/ipmid/message.hpp>
+#include <ipmid/message.hpp>
 #include <ipmid/message/types.hpp>
 #include <phosphor-logging/lg2.hpp>
 #include <phosphor-logging/log.hpp>
diff --git a/include/ipmid/message/unpack.hpp b/include/ipmid/message/unpack.hpp
index 357f0b4..2e545b0 100644
--- a/include/ipmid/message/unpack.hpp
+++ b/include/ipmid/message/unpack.hpp
@@ -15,7 +15,7 @@
  */
 #pragma once
 
-#include <include/ipmid/message.hpp>
+#include <ipmid/message.hpp>
 #include <ipmid/message/types.hpp>
 
 #include <array>