support chained scatterlists for aead, ablkcipher and ahash.
Signed-off-by: NYuan Kang <Yuan.Kang@freescale.com>

- fix dma unmap leak
- un-unlikely src == dst, due to experience with AF_ALG
Signed-off-by: NKudupudi Ugendreshwar <B38865@freescale.com>
Signed-off-by: NKim Phillips <kim.phillips@freescale.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>