crypto: atmel-aes - Fix CTR counter overflow when multiple fragments

The CTR transfer works in fragments of data of maximum 1 MByte because
of the 16 bit CTR counter embedded in the IP. Fix the CTR counter
overflow handling for messages larger than 1 MByte.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 781a08d9

 ("crypto: atmel-aes - Fix counter overflow in CTR mode")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>