crypto: marvell/cesa - rename blkcipher to skcipher

The driver specific types contain some rudimentary references to the
blkcipher API, which is deprecated and will be removed. To avoid confusion,
rename these to skcipher. This is a cosmetic change only, as the code does
not actually use the blkcipher API.

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