csr wb master: fixing almost_full threshold

The sizes of to_wb and from_wb fifo were reduced in commit 4a430afa from 512 to
128 words. However, almost_full thresholds were still set to 500. As the
result some of the requests were lost when fifo was full because this fact was
never signaled to the gn4124 chip.

hdl/gn4124core/rtl/wbmaster32.vhd

@@ -118,8 +118,10 @@ architecture behaviour of wbmaster32 is
   -----------------------------------------------------------------------------
   -- Constants declaration
   -----------------------------------------------------------------------------
-  constant c_TO_WB_FIFO_FULL_THRES   : integer := 500;
-  constant c_FROM_WB_FIFO_FULL_THRES : integer := 500;
+  constant c_TO_WB_FIFO_SIZE         : integer := 128;
+  constant c_TO_WB_FIFO_FULL_THRES   : integer := 110;
+  constant c_FROM_WB_FIFO_SIZE       : integer := 128;
+  constant c_FROM_WB_FIFO_FULL_THRES : integer := 110;
 
   -----------------------------------------------------------------------------
   -- Signals declaration
@@ -315,7 +317,7 @@ begin
   cmp_fifo_to_wb : generic_async_fifo
     generic map (
       g_data_width             => 64,
-      g_size                   => 128,
+      g_size                   => c_TO_WB_FIFO_SIZE,
       g_show_ahead             => false,
       g_with_rd_empty          => true,
       g_with_rd_full           => false,
@@ -356,7 +358,7 @@ begin
   cmp_from_wb_fifo : generic_async_fifo
     generic map (
       g_data_width             => 32,
-      g_size                   => 128,
+      g_size                   => c_FROM_WB_FIFO_SIZE,
       g_show_ahead             => false,
       g_with_rd_empty          => true,
       g_with_rd_full           => false,