Shared descriptors for hash algorithms are small enough
for (split) keys to be inlined in all cases.
Since driver already does this, all what's left is to remove
unused ctx->key_dma.

Fixes: 045e3678 ("crypto: caam - ahash hmac support")
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>