s390x: fix compilation error due to typo

Change-Id: I048f1f1ba6018681370681d5fca33bc09cfca47e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2643135Reviewed-by: Milad Fa <mfarazma@redhat.com>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/master@{#72261}

src/codegen/s390/macro-assembler-s390.cc

@@ -3739,14 +3739,14 @@ void TurboAssembler::StoreU16LE(Register src, const MemOperand& mem,
 
 void TurboAssembler::StoreF64LE(DoubleRegister src, const MemOperand& opnd,
                                 Register scratch) {
-  DCHECK(!is_int20(mem.offset()));
+  DCHECK(!is_int20(opnd.offset()));
   lgdr(scratch, src);
   strvg(scratch, opnd);
 }
 
 void TurboAssembler::StoreF32LE(DoubleRegister src, const MemOperand& opnd,
                                 Register scratch) {
-  DCHECK(!is_int20(mem.offset()));
+  DCHECK(!is_int20(opnd.offset()));
   lgdr(scratch, src);
   ShiftRightU64(scratch, scratch, Operand(32));
   strv(scratch, opnd);