[rtl] Move counter_q definition

The counter_q definition should be outside of the if else such that
we have the correct scope. Moreover, Xilinx Vivado reports an
error if the DspPragma is a string instead of an int. Finally,
Xilinx complained that COUNTER_FLOP_RST is redefined.

Signed-off-by: Pascal Nasahl <nasahlpa@lowrisc.org>

rtl/ibex_counter.sv

@@ -50,33 +50,46 @@ module ibex_counter #(
     end
   end
 
+`define ASYNC_RST_FF(CLK, RST_NI, Q, D) \
+  always_ff @(posedge CLK or negedge RST_NI) begin \
+    if (!RST_NI) begin \
+      Q <= '0; \
+    end else begin \
+      Q <= D; \
+    end \
+  end
+
+`define SYNC_RST_FF(CLK, RST_NI, Q, D) \
+  always_ff @(posedge CLK) begin \
+    if (!RST_NI) begin \
+      Q <= '0; \
+    end else begin \
+      Q <= D; \
+    end \
+  end
+
 `ifdef FPGA_XILINX
   // On Xilinx FPGAs, 48-bit DSPs are available that can be used for the
   // counter.
-  if (CounterWidth < 49) begin : g_dsp_counter
-    // Set DSP pragma for supported xilinx FPGAs
-    (* use_dsp = "yes" *) logic [CounterWidth-1:0] counter_q;
-    // DSP output register requires synchronous reset.
-    `define COUNTER_FLOP_RST posedge clk_i
-  end else begin : g_no_dsp_counter
-    (* use_dsp = "no" *) logic [CounterWidth-1:0] counter_q;
-    `define COUNTER_FLOP_RST posedge clk_i or negedge rst_ni
-  end
+  localparam int DspPragma = CounterWidth < 49 ? "yes" : "no";
+  (* use_dsp = DspPragma *) logic [CounterWidth-1:0] counter_q;
+  // When using a DSP, a synchronous reset is needed.
+  localparam string ResetType = CounterWidth < 49 ? "SYNC" : "ASYNC";
 `else
   logic [CounterWidth-1:0] counter_q;
-
-  `define COUNTER_FLOP_RST posedge clk_i or negedge rst_ni
+  localparam string ResetType = "ASYNC";
 `endif
 
   // Counter flop
-  always_ff @(`COUNTER_FLOP_RST) begin
-  `undef COUNTER_FLOP_RST
-    if (!rst_ni) begin
-      counter_q <= '0;
-    end else begin
-      counter_q <= counter_d;
+  generate
+    if(ResetType == "ASYNC") begin : g_async_reset_ff
+      `ASYNC_RST_FF(clk_i, rst_ni, counter_q, counter_d);
+      `undef ASYNC_RST_FF
+    end else begin : g_sync_reset_ff
+      `SYNC_RST_FF(clk_i, rst_ni, counter_q, counter_d);
+      `undef SYNC_RST_FF
     end
-  end
+  endgenerate
 
   if (CounterWidth < 64) begin : g_counter_narrow
     logic [63:CounterWidth] unused_counter_load;