ARM: ux500: Pass remnant platform data though to DMA40 driver

Ironically, in order to remove lots of the auxdata assignments, we have
to add just one more. A lot of them require DMA information to be passed
into clients for DMA channel allocation, but we now have this capability
in Device Tree. However, the DMA40 driver still relies on a reverse table
look-up to obtain DMA addresses. Until all of the clients are converted,
over to the new API, we're stuck with this.

Also, now the DMA40 has been DT:ed, there's no requirement to register
it using traditional methods, so let's remove it.

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>