ftm4dp: add rstn_ref signal

top/gsi_scu/ftm4dp/ftm4dp.vhd

@@ -189,6 +189,7 @@ architecture rtl of ftm4dp is
  signal s_stub_pll_reset : std_logic;
  signal s_stub_pll_locked : std_logic;
  signal s_stub_pll_locked_prev : std_logic;
+ signal rstn_ref : std_logic;
 
  signal s_i2c_scl_pad_out : std_logic_vector(1 downto 1);
  signal s_i2c_scl_pad_in : std_logic_vector(1 downto 1);