Add a global defines.v and rely less on parameters

- This is mainly to avoid "accidents" with default parameter values
diff --git a/verilog/rtl/mem_synth_wb.v b/verilog/rtl/mem_synth_wb.v
index d54ddf6..c4a1cc4 100644
--- a/verilog/rtl/mem_synth_wb.v
+++ b/verilog/rtl/mem_synth_wb.v
@@ -1,6 +1,4 @@
-module mem_synth_wb #(
-   parameter integer MEM_WORDS = 1024
-)( 
+module mem_synth_wb ( 
     input wb_clk_i,
     input wb_rst_i,
 
@@ -37,9 +35,7 @@
         end
     end
 
-    soc_mem_synth # (
-        .MEM_WORDS(MEM_WORDS)
-    ) mem (
+    soc_mem_synth mem (
         .clk(wb_clk_i),
         .ena(valid),
         .wen(wen),
@@ -50,9 +46,7 @@
 
 endmodule
 
-module soc_mem_synth #(
-    parameter integer MEM_WORDS = 2048
-)(
+module soc_mem_synth (
     input clk,
     input ena,
     input [3:0] wen,
@@ -62,7 +56,7 @@
 );
 
     reg [31:0] rdata;
-    reg [31:0] mem [0:MEM_WORDS-1];
+    reg [31:0] mem [0:`MEM_SYNTH_WORDS-1];
 
     always @(posedge clk) begin
         if (ena == 1'b1) begin
@@ -74,4 +68,4 @@
         end
     end
 
-endmodule
\ No newline at end of file
+endmodule