change: remove jerry-riged hysteresis based receiver from hi_read_tx

This future got obsolete by a x-correlation based receiver.

This reverts commit 24fe4dffb4.

fpga/hi_read_tx.v

@@ -71,19 +71,8 @@ always @(negedge ssp_clk)
 
 assign ssp_frame = (hi_byte_div == 3'b000);
 
-// Implement a hysteresis to give out the received signal on
-// ssp_din. Sample at fc.
-assign adc_clk = ck_1356meg;
+assign ssp_din = 1'b0;
 
-// ADC data appears on the rising edge, so sample it on the falling edge
-reg after_hysteresis;
-always @(negedge adc_clk)
-begin
-    if(& adc_d[6:4]) after_hysteresis <= 1'b1;
-    else if(~(| adc_d[6:4])) after_hysteresis <= 1'b0;
-end
+assign dbg = ssp_frame;
 
-assign ssp_din = after_hysteresis;
-assign dbg = after_hysteresis;
-
-endmodule
+endmodule