Disable verilator warnings, fixes #128

Signed-off-by: Clifford Wolf <clifford@clifford.at>

picorv32.v

@@ -17,6 +17,11 @@
  *
  */
 
+/* verilator lint_off WIDTH */
+/* verilator lint_off PINMISSING */
+/* verilator lint_off CASEOVERLAP */
+/* verilator lint_off CASEINCOMPLETE */
+
 `timescale 1 ns / 1 ps
 // `default_nettype none
 // `define DEBUGNETS