Added missing hash_func.h header

h_table.h uses TABLE_ENTRIES macro but did not include hash_func.h
where the macro is defined. When h_table.h is included from another
modules which does not include hash_func.h then the modules does
not compile

modules/tm/h_table.h

@@ -71,6 +71,7 @@
 #include "../../usr_avp.h"
 #include "../../timer.h"
 #include "../../atomic_ops.h"
+#include "../../hash_func.h"
 #include "config.h"
 
 /* if TM_DIFF_RT_TIMEOUT is defined, different retransmissions timeouts