wishbone_pkg: remove useless dependency.

modules/wishbone/wishbone_pkg.vhd

@@ -28,9 +28,6 @@ library ieee;
 use ieee.std_logic_1164.all;
 use ieee.numeric_std.all;
 
-library work;
-use work.genram_pkg.all;
-
 package wishbone_pkg is
 
   constant c_wishbone_address_width : integer := 32;