[SPARC] Remove superfluous memory barrier for atomics with TSO

[David Miller]

From: Richard Henderson <rth@redhat.com>
Date: Tue, 30 Jul 2013 12:33:30 -1000

> On 07/30/2013 03:31 AM, Eric Botcazou wrote:
>> 2013-07-30  Eric Botcazou  <ebotcazou@adacore.com>
>> 
>> 	* config/sparc/sparc.c (sparc_emit_membar_for_model) <SMM_TSO>: Add
>> 	the implied StoreLoad barrier for atomic operations if before.
> 
> Looks good.

This looks fine to me too.