[MIPS] Fix method tracing for mips64

Reg $v0 is being clobbered on using
SETUP_REFS_ONLY_CALLEE_SAVE_FRAME inside instrumentation_exit()
trampoline, when falling through from instrumentation_entry().

To fix, use $t1 for ArtMethod* fetching inside SETUP_ macros.

Also fix some unrelated comment errors.

Change-Id: I4ab169f75988c4f0d924416a30196f21c1a043a3
diff --git a/runtime/arch/mips/quick_entrypoints_mips.S b/runtime/arch/mips/quick_entrypoints_mips.S
index 3a0ea64..cc1de43 100644
--- a/runtime/arch/mips/quick_entrypoints_mips.S
+++ b/runtime/arch/mips/quick_entrypoints_mips.S
@@ -380,7 +380,7 @@
     /*
      * Called by managed code, saves most registers (forms basis of long jump context) and passes
      * the bottom of the stack. artDeliverExceptionFromCode will place the callee save Method* at
-     * the bottom of the thread. On entry r0 holds Throwable*
+     * the bottom of the thread. On entry a0 holds Throwable*
      */
 ENTRY art_quick_deliver_exception
     SETUP_SAVE_ALL_CALLEE_SAVE_FRAME