PEL: Add missing <map> include to callouts.cpp

This won't come for free starting in a future commit.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I4bdb44ab60c688d71336992bc6e97d8192931aec
diff --git a/extensions/openpower-pels/callouts.cpp b/extensions/openpower-pels/callouts.cpp
index ae95d3e..0185fc2 100644
--- a/extensions/openpower-pels/callouts.cpp
+++ b/extensions/openpower-pels/callouts.cpp
@@ -18,6 +18,7 @@
 #include "trace.hpp"
 
 #include <algorithm>
+#include <map>
 
 namespace openpower
 {