init

We can make the code read more easily here by simply using memset()
always as when we don't have an optimized version of the function we
will still have a version of this function around anyhow.

Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>