Fix compile error on IA64

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/arch/arch-ia64.h b/arch/arch-ia64.h
index 2f92684..a8bb23a 100644
--- a/arch/arch-ia64.h
+++ b/arch/arch-ia64.h
@@ -20,7 +20,7 @@
 
 #define nop		asm volatile ("hint @pause" ::: "memory");
 #define read_barrier()	asm volatile ("mf" ::: "memory")
-#define writebarrier()	asm volatile ("mf" ::: "memory")
+#define write_barrier()	asm volatile ("mf" ::: "memory")
 
 #define ia64_popcnt(x)							\
 ({									\