UPSTREAM: crypto: scatterwalk - remove 'chain' argument from scatterwalk_crypto_chain()

All callers pass chain=0 to scatterwalk_crypto_chain().

Remove this unneeded parameter.

Change-Id: I77f426f8d95b1b65b8ff8847010413711b7112f4
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>