hwrng: iproc-rng200 - Add support for BCM2711

BCM2711 features a RNG200 hardware random number generator block.
So make the driver available.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Signed-off-by: Stephen Brennan <stephen@brennan.io>
Reviewed-by: Matthias Brugger <mbrugger@suse.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>