We normally use __weak rather than calling it out directly as an alias.
Update this function to the normal method.

Signed-off-by: Tom Rini <trini@konsulko.com>

The default implementation of this function is just memset, but other
implementations will be needed when physical memory isn't accessible by
U-Boot using normal addressing mechanisms.

Signed-off-by: Gabe Black <gabeblack@chromium.org>
Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>