crypto: xts - Only add ecb if it is not already there

[ Upstream commit 270b6f13 ]

Only add ecb to the cipher name if it isn't already ecb.

Also use memcmp instead of strncmp since these strings are all
stored in an array of length CRYPTO_MAX_ALG_NAME.

Fixes: f1c131b4 ("crypto: xts - Convert to skcipher")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>