staging: ccree: do not map bufs in ahash_init

hash_init was mapping DMA memory that were then being unmap in
hash_digest/final/finup callbacks, which is against the Crypto API
usage rules (see discussion at
https://www.mail-archive.com/linux-crypto@vger.kernel.org/msg30077.html)

Fix it by moving all buffer mapping/unmapping or each Crypto API op.

This also properly deals with hash_import() not knowing if
hash_init was called or not as it now no longer matters.
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>