crypto: marvell - Move tdma chain out of mv_cesa_tdma_req and remove it

Currently, the only way to access the tdma chain is to use the 'req'
union from a mv_cesa_{ablkcipher,ahash}. This will soon become a problem
if we want to handle the TDMA chaining vs standard/non-DMA processing in
a generic way (with generic functions at the cesa.c level detecting
whether the request should be queued at the DMA level or not). Hence the
decision to move the chain field a the mv_cesa_req level at the expense
of adding 2 void * fields to all request contexts (including non-DMA
ones) and to remove the type completly. To limit the overhead, we get
rid of the type field, which can now be deduced from the req->chain.first
value. Once these changes are done the union is no longer needed, so
remove it and move mv_cesa_ablkcipher_std_req and mv_cesa_req
to mv_cesa_ablkcipher_req directly. There are also no needs to keep the
'base' field into the union of mv_cesa_ahash_req, so move it into the
upper structure.

Signed-off-by: Romain Perier <romain.perier@free-electrons.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>