l2tlb: fix ecc width (#1584)

src/main/scala/xiangshan/cache/mmu/MMUBundle.scala

@@ -639,9 +639,9 @@ class PTWEntriesWithEcc(eccCode: Code, num: Int, tagLen: Int, level: Int, hasPer
     val data = entries.asUInt()
     val res = Wire(Vec(ecc_info._3 + 1, Bool()))
     for (i <- 0 until ecc_info._3) {
-      res(i) := eccCode.decode(Cat(ecc((i+1)*ecc_info._2-1, i*ecc_info._2), data((i+1)*ecc_block-1, i*ecc_block))).error
+      res(i) := {if (ecc_info._2 != 0) eccCode.decode(Cat(ecc((i+1)*ecc_info._2-1, i*ecc_info._2), data((i+1)*ecc_block-1, i*ecc_block))).error else false.B}
     }
-    if (ecc_info._4 != 0) {
+    if (ecc_info._2 != 0 && ecc_info._4 != 0) {
       res(ecc_info._3) := eccCode.decode(
         Cat(ecc(ecc_info._1-1, ecc_info._2*ecc_info._3), data(data.getWidth-1, ecc_info._3*ecc_block))).error
     } else { res(ecc_info._3) := false.B }