dm: updating crypto algorithm used by dm-req-crypt

dm-req-crypt uses AES-XTS algorithm implemented by HW crypto
engine. Crypto driver renamed the aes-xts algorithm to avoid
conflict with SW based implementation of AES-XTS. dm-req-crypt
must use the new name for AES-XTS provided by crypto driver.

Change-Id: I286b6435af33fd64673c7c1af4bb2447f3115868
Signed-off-by: Dinesh K Garg <dineshg@codeaurora.org>