crypto: axis - move request unmap outside of the queue lock

The request unmap and bounce buffer copying is currently unnecessarily
done while holding the queue spin lock.

Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: Vincent Whitchurch <rabinv@axis.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>