Fix Verilator 5.010 compilation error

Verilator was throwing a compilation error due to
MULTIDRIVEN and BLKSEQ in ibex_tracer.sv

This change ensures successful compilation with Verilator 5.010

rtl/ibex_tracer.sv

@@ -116,7 +116,9 @@ module ibex_tracer (
       $sformat(file_name, "%s_%h.log", file_name_base, hart_id_i);
 
       $display("%m: Writing execution trace to %s", file_name);
+      /* verilator lint_off BLKSEQ */
       file_handle = $fopen(file_name, "w");
+      /* verilator lint_on BLKSEQ */
       $fwrite(file_handle,
               "Time\tCycle\tPC\tInsn\tDecoded instruction\tRegister and memory contents\n");
     end
@@ -759,8 +761,10 @@ module ibex_tracer (
   end
 
   always_comb begin
+    /* verilator lint_off MULTIDRIVEN */
     decoded_str = "";
     data_accessed = 5'h0;
+    /* verilator lint_on MULTIDRIVEN */
     insn_is_compressed = 0;
 
     // Check for compressed instructions