[PATCH v3] Add sync to ensure flash_write_cmd is fully finished

Some CPUs like PPC, BLACKFIN need sync() to ensure cfi flash write command
is fully finished. The sync() is defined in each CPU's io.h file. For
those CPUs which do not need sync for now, a dummy sync() is defined in
their io.h as well.

Signed-off-by: Haiying Wang <Haiying.Wang@freescale.com>
diff --git a/include/asm-arm/io.h b/include/asm-arm/io.h
index 648a10d..47c18e7 100644
--- a/include/asm-arm/io.h
+++ b/include/asm-arm/io.h
@@ -29,6 +29,10 @@
 #include <asm/arch/hardware.h>
 #endif	/* XXX###XXX */
 
+static inline void sync(void)
+{
+}
+
 /*
  * Generic virtual read/write.  Note that we don't support half-word
  * read/writes.  We define __arch_*[bl] here, and leave __arch_*w