driver
will aceesss to a unallocated region.

Acked-by: Dong Aisheng <dong.aisheng@linaro.org>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Hui Wang <jason77.wang@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
x¯