crypto: lskcipher - Add compatibility wrapper around ECB

As an aid to the transition from cipher algorithm implementations
to lskcipher, add a temporary wrapper when creating simple lskcipher
templates by using ecb(X) instead of X if an lskcipher implementation
of X cannot be found.

This can be reverted once all cipher implementations have switched
over to lskcipher.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>