crypto: atmel - Fix dma_unmap_sg() direction

It seems like everywhere in this file, dd->in_sg is mapped with
DMA_TO_DEVICE and dd->out_sg is mapped with DMA_FROM_DEVICE.

Fixes: 13802005 ("crypto: atmel - add Atmel DES/TDES driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>