PPC: [cleanup] Eliminate non-const reference parameters

Port af063685

R=bbudge@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: Iccbb0a968cd8490cfa1191ea8adb31007739b297
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1790544Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63634}

src/codegen/constant-pool.h

@@ -102,13 +102,13 @@ class ConstantPoolBuilder {
   ConstantPoolEntry::Access AddEntry(int position, intptr_t value,
                                      bool sharing_ok) {
     ConstantPoolEntry entry(position, value, sharing_ok);
-    return AddEntry(entry, ConstantPoolEntry::INTPTR);
+    return AddEntry(&entry, ConstantPoolEntry::INTPTR);
   }
 
   // Add double constant to the embedded constant pool
   ConstantPoolEntry::Access AddEntry(int position, Double value) {
     ConstantPoolEntry entry(position, value);
-    return AddEntry(entry, ConstantPoolEntry::DOUBLE);
+    return AddEntry(&entry, ConstantPoolEntry::DOUBLE);
   }
 
   // Add double constant to the embedded constant pool