crypto: ux500 - Update DMA handling for 3.4

An update to the DMA framework added a new parameter to the
device_prep_slave_sg call.

Signed-off-by: Andreas Westin <andreas.westin@stericsson.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>