[mips][Liftoff] Fix stack slot initialization on mips

Port 7d09b270

Original Commit Message:

    It turns out that because we are *subtracting* from fp, we need to
    *subtract less* to get a higher address. Who knew.

R=xwafish@gmail.com, clemensb@chromium.org

Change-Id: I1ddb5e15ef7fab2f198aebf07a5ce607add4c3c4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1868559
Auto-Submit: Mu Tao <pamilty@gmail.com>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64406}

src/wasm/baseline/mips/liftoff-assembler-mips.h

@@ -624,8 +624,7 @@ void LiftoffAssembler::FillStackSlotsWithZero(uint32_t index, uint32_t count) {
     // Use a0 for start address (inclusive), a1 for end address (exclusive).
     Push(a1, a0);
     Addu(a0, fp, Operand(-liftoff::GetStackSlotOffset(last_stack_slot)));
-    Addu(a1, fp,
-         Operand(-(liftoff::GetStackSlotOffset(index) + kStackSlotSize)));
+    Addu(a1, fp, Operand(-liftoff::GetStackSlotOffset(index) + kStackSlotSize));
 
     Label loop;
     bind(&loop);

src/wasm/baseline/mips64/liftoff-assembler-mips64.h

@@ -544,7 +544,7 @@ void LiftoffAssembler::FillStackSlotsWithZero(uint32_t index, uint32_t count) {
     Push(a1, a0);
     Daddu(a0, fp, Operand(-liftoff::GetStackSlotOffset(last_stack_slot)));
     Daddu(a1, fp,
-          Operand(-(liftoff::GetStackSlotOffset(index) + kStackSlotSize)));
+          Operand(-liftoff::GetStackSlotOffset(index) + kStackSlotSize));
 
     Label loop;
     bind(&loop);