wishbone: Add stall signal

Pipelined wishbone needs it

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

wishbone_types.vhdl

@@ -23,7 +23,8 @@ package wishbone_types is
     type wishbone_slave_out is record
         dat   : wishbone_data_type;
         ack   : std_ulogic;
+        stall : std_ulogic;
     end record;
-    constant wishbone_slave_out_init : wishbone_slave_out := (ack => '0', others => (others => '0'));
+    constant wishbone_slave_out_init : wishbone_slave_out := (ack => '0', stall => '0', others => (others => '0'));
 
 end package wishbone_types;