crypto: inside-secure - keep the requests push/pop synced

This patch updates the Inside Secure SafeXcel driver to avoid being
out-of-sync between the number of requests sent and the one being
completed.

The number of requests acknowledged by the driver can be different than
the threshold that was configured if new requests were being pushed to
the h/w in the meantime. The driver wasn't taking those into account,
and the number of remaining requests to handled (to reconfigure the
interrupt threshold) could be out-of sync.

This patch fixes it by not taking in account the number of requests
left, but by taking in account the total number of requests being sent
to the hardware, so that new requests are being taken into account.

Fixes: dc7e28a3 ("crypto: inside-secure - dequeue all requests at once")
Suggested-by: Ofer Heifetz <oferh@marvell.com>
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>