8139421: PPC64LE: MacroAssembler::bxx64_patchable kill register R12

Summary: Register R12 must be preserved for stub calls (e.g. deopt handler).
Reviewed-by: goetz

src/cpu/ppc/vm/macroAssembler_ppc.cpp

@@ -592,13 +592,6 @@ void MacroAssembler::bxx64_patchable(address dest, relocInfo::relocType rt, bool
            "can't identify emitted call");
   } else {
     // variant 1:
-#if defined(ABI_ELFv2)
-    nop();
-    calculate_address_from_global_toc(R12, dest, true, true, false);
-    mtctr(R12);
-    nop();
-    nop();
-#else
     mr(R0, R11);  // spill R11 -> R0.
 
     // Load the destination address into CTR,
@@ -608,7 +601,6 @@ void MacroAssembler::bxx64_patchable(address dest, relocInfo::relocType rt, bool
     mtctr(R11);
     mr(R11, R0);  // spill R11 <- R0.
     nop();
-#endif
 
     // do the call/jump
     if (link) {