Fix a clang-tidy warning in VisitVarHandleGetAndAdd()

Fixes a commented argument name mismatch in
IntrinsicCodeGeneratorX86::VisitVarHandleGetAndAdd().

Bug: 168883594
Test: WITH_TIDY=1 m
Change-Id: I526dbe05610301d34457a735dee5fe162ab3230a
diff --git a/compiler/optimizing/intrinsics_x86.cc b/compiler/optimizing/intrinsics_x86.cc
index 4e24aab..3017a32 100644
--- a/compiler/optimizing/intrinsics_x86.cc
+++ b/compiler/optimizing/intrinsics_x86.cc
@@ -3913,7 +3913,7 @@
               value_loc.AsFpuRegister<XmmRegister>());
       GenPrimitiveLockedCmpxchg(type,
                                 codegen,
-                                /* expected= */ eax,
+                                /* expected_value= */ eax,
                                 /* new_value= */ temp_float,
                                 reference,
                                 offset,