[HIFN]: Fix data alignment checks

    
The check for misalignment of the scatterlist data has two bugs:

- the source buffer doesn't need to be aligned at all
- the destination buffer and its size needs to be aligned to a multiple
  of 4, not to the crypto alg blocksize
    
Introduce symbolic constant for destination buffer alignment requirements,
use it instead of the crypto alg blocksize and remove the unnecessary
checks for source buffer alignment and change cra_alignmask to zero.
    
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>