Crypto/chcr: support for 48 byte key_len in aes-xts

Added support for 48 byte key length for aes-xts.

Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: Devulapally Shiva Krishna <shiva@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>