ARM: ux500: Stop passing DMA platform data though AUXDATA

The DMA platform data is now empty due to some recent refactoring,
so there is no longer a requirement to pass it though.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>