style: [patch 3/22] reduce include dependencies in some headers

Used cppclean to help identify useless includes and removed them. This
involved erroneously included headers, but also cases where forward
declarations could have been used rather than a full include.

src/sim/syscall_return.hh

@@ -31,7 +31,7 @@
 #ifndef __SIM_SYSCALLRETURN_HH__
 #define __SIM_SYSCALLRETURN_HH__
 
-#include "base/types.hh"
+#include <inttypes.h>
 
 /**
  * This class represents the return value from an emulated system call,