Clarified IN as default constant instead of SIGNAL in proc_dp_verify_sync().

libraries/base/dp/tb/vhdl/tb_dp_pkg.vhd

@@ -477,6 +477,9 @@ PACKAGE tb_dp_pkg IS
                                          bsn           : IN    NATURAL;  -- for reporting
                                          expected_bsn  : IN    NATURAL;  -- for reporting
                                          expected_sync : IN    STD_LOGIC);
+    -- Note: A SIGNAL IN can only connect a SIGNAL. Therefore define IN as
+    --       default (= CONSTANT) instead of SIGNAL to be able to connect
+    --       VARIABLE or SIGNAL.
 
   PROCEDURE proc_dp_verify_sync(CONSTANT c_sync_period : IN    NATURAL;
                                 CONSTANT c_sync_offset : IN    NATURAL;