Use ATTRIBUTE_UNUSED more.

Use it in lieu of UNUSED(), which had some incorrect uses.

Change-Id: If247dce58b72056f6eea84968e7196f0b5bef4da
diff --git a/compiler/dex/quick/x86/target_x86.cc b/compiler/dex/quick/x86/target_x86.cc
index c62cd47..25fb886 100755
--- a/compiler/dex/quick/x86/target_x86.cc
+++ b/compiler/dex/quick/x86/target_x86.cc
@@ -254,8 +254,7 @@
                        : RegStorage32FromSpecialTargetRegister_Target32[reg];
 }
 
-RegStorage X86Mir2Lir::TargetReg(SpecialTargetRegister reg) {
-  UNUSED(reg);
+RegStorage X86Mir2Lir::TargetReg(SpecialTargetRegister reg ATTRIBUTE_UNUSED) {
   LOG(FATAL) << "Do not use this function!!!";
   UNREACHABLE();
 }
@@ -861,8 +860,7 @@
 }
 
 // Not used in x86(-64)
-RegStorage X86Mir2Lir::LoadHelper(QuickEntrypointEnum trampoline) {
-  UNUSED(trampoline);
+RegStorage X86Mir2Lir::LoadHelper(QuickEntrypointEnum trampoline ATTRIBUTE_UNUSED) {
   LOG(FATAL) << "Unexpected use of LoadHelper in x86";
   UNREACHABLE();
 }
@@ -2323,13 +2321,11 @@
   }
 }
 
-void X86Mir2Lir::GenPackedArrayGet(BasicBlock* bb, MIR* mir) {
-  UNUSED(bb, mir);
+void X86Mir2Lir::GenPackedArrayGet(BasicBlock* bb ATTRIBUTE_UNUSED, MIR* mir ATTRIBUTE_UNUSED) {
   UNIMPLEMENTED(FATAL) << "Extended opcode kMirOpPackedArrayGet not supported.";
 }
 
-void X86Mir2Lir::GenPackedArrayPut(BasicBlock* bb, MIR* mir) {
-  UNUSED(bb, mir);
+void X86Mir2Lir::GenPackedArrayPut(BasicBlock* bb ATTRIBUTE_UNUSED, MIR* mir ATTRIBUTE_UNUSED) {
   UNIMPLEMENTED(FATAL) << "Extended opcode kMirOpPackedArrayPut not supported.";
 }