ARM: ux500: fix ureachable iounmap()

The code was executing a return with a pointer before reaching
iounmap().

Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>