crypto: authenc - Correctly pass EINPROGRESS back up to the caller

crypto: authenc - Correctly pass EINPROGRESS back up to the caller

When authenc is invoked with MAY_BACKLOG, it needs to pass EINPROGRESS
notifications back up to the caller when the underlying algorithm
returns EBUSY synchronously.

However, if the EBUSY comes from the second part of an authenc call,
i.e., it is asynchronous, both the EBUSY and the subsequent EINPROGRESS
notification must not be passed to the caller.

Implement this by passing a mask to the function that starts the
second half of authenc and using it to determine whether EBUSY
and EINPROGRESS should be passed to the caller.

This was a deficiency in the original implementation of authenc
because it was not expected to be used with MAY_BACKLOG.

Reported-by: Ingo Franzki <ifranzki@linux.ibm.com>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 180ce7e81030 ("crypto: authenc - Add EINPROGRESS check")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>