Apply misc-include-cleaner fixes

misc-include-cleaner seems to have found a lot more things all of a
sudden.  Unclear why the result has changed, but we can just fix the
issues.

Tested: Clang-tidy now passes.  Code compiles.

Change-Id: Iab045cc183f0daef663b4d5ac901200a42807987
Signed-off-by: Ed Tanous <etanous@nvidia.com>
diff --git a/src/mctp/MCTPReactor.hpp b/src/mctp/MCTPReactor.hpp
index ca20b45..2030e45 100644
--- a/src/mctp/MCTPReactor.hpp
+++ b/src/mctp/MCTPReactor.hpp
@@ -4,6 +4,11 @@
 #include "MCTPEndpoint.hpp"
 #include "Utils.hpp"
 
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <optional>
+#include <set>
 #include <string>
 #include <vector>