crypto: sun8i-ce - move fallback ahash_request to the end of the struct

'struct ahash_request' has a flexible array at the end, so it must be the
last member in a struct, to avoid overwriting other struct members.

Therefore, move 'fallback_req' to the end of the 'sun8i_ce_hash_reqctx'
struct.

Fixes: 56f6d5ae ("crypto: sun8i-ce - support hash algorithms")
Signed-off-by: Ovidiu Panait <ovidiu.panait.oss@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>