crypto: skcipher - Get rid of crypto_grab_skcipher2()

crypto: skcipher - Get rid of crypto_grab_skcipher2()

Since commit 6d9831ec518a ("crypto: skcipher - Remove top-level
givcipher interface"), crypto_grab_skcipher2() and
crypto_grab_skcipher() are equivalent.  So switch callers of
crypto_grab_skcipher2() to crypto_grab_skcipher() and remove it.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>