Remove last trace of CONFIG_UNORDERED_IO

This was an experiment that failed. The Kconfig entry is gone for
some time; remove the last ifdef too.

Signed-off-by: Andi Kleen <ak@suse.de>

---
 include/asm-x86_64/system.h |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

Index: linux/include/asm-x86_64/system.h
===================================================================
--- linux.orig/include/asm-x86_64/system.h
+++ linux/include/asm-x86_64/system.h
@@ -164,12 +164,8 @@ static inline void clflush(volatile void
  */
 #define mb() 	asm volatile("mfence":::"memory")
 #define rmb()	asm volatile("lfence":::"memory")
+#define wmb()	barrier()
 
-#ifdef CONFIG_UNORDERED_IO
-#define wmb()	asm volatile("sfence" ::: "memory")
-#else
-#define wmb()	asm volatile("" ::: "memory")
-#endif
 #define read_barrier_depends()	do {} while(0)
 #define set_mb(var, value) do { (void) xchg(&var, value); } while (0)