crypto: hash - Fix async import on shash algorithm

The function shash_async_import did not initialise the descriptor
correctly prior to calling the underlying shash import function.

This patch adds the required initialisation.

Reported-by: Miloslav Trmac <mitr@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --cc crypto/shash.c
Simple merge