crypto: inside-secure - add multiple processing engine support

So far a single processing engine (PE) was configured and used in the
Inside Secure SafeXcel cryptographic engine driver. Some versions have
more than a single PE. This patch rework the driver's initialization to
take this into account and to allow configuring more than one PE.

Signed-off-by: Ofer Heifetz <oferh@marvell.com>
[Antoine: some reworks and commit message.]
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>