[mips64] Port `[memory] Replace Memory class with templated Memory functions.`

Original commit d67d91db

Change-Id: I2787a090e8794b91a7f08635ce73f925e1021477
Reviewed-on: https://chromium-review.googlesource.com/1188317Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Sreten Kovacevic <skovacevic@wavecomp.com>
Cr-Commit-Position: refs/heads/master@{#55396}

src/mips64/assembler-mips64-inl.h

@@ -148,7 +148,7 @@ void Assembler::deserialization_set_target_internal_reference_at(
     set_target_internal_reference_encoded_at(pc, target);
   } else {
     DCHECK(mode == RelocInfo::INTERNAL_REFERENCE);
-    Memory::Address_at(pc) = target;
+    Memory<Address>(pc) = target;
   }
 }
 
@@ -191,7 +191,7 @@ void RelocInfo::set_target_external_reference(
 
 Address RelocInfo::target_internal_reference() {
   if (rmode_ == INTERNAL_REFERENCE) {
-    return Memory::Address_at(pc_);
+    return Memory<Address>(pc_);
   } else {
     // Encoded internal references are j/jal instructions.
     DCHECK(rmode_ == INTERNAL_REFERENCE_ENCODED);
@@ -233,7 +233,7 @@ void RelocInfo::WipeOut() {
          IsInternalReference(rmode_) || IsInternalReferenceEncoded(rmode_) ||
          IsOffHeapTarget(rmode_));
   if (IsInternalReference(rmode_)) {
-    Memory::Address_at(pc_) = kNullAddress;
+    Memory<Address>(pc_) = kNullAddress;
   } else if (IsInternalReferenceEncoded(rmode_)) {
     Assembler::set_target_internal_reference_encoded_at(pc_, kNullAddress);
   } else {