crypto: atmel-aes - fix atmel_aes_handle_queue()

This patch fixes the value returned by atmel_aes_handle_queue(), which
could have been wrong previously when the crypto request was started
synchronously but became asynchronous during the ctx->start() call.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>