hwrng: cn10k - Add extended trng register support

The way random data is read from hardware has changed from
Octeon CN10KA-B0 and later SoCs onwards. A new set of registers
have been added to read random data and to verify whether the
read data is valid or not. This patch extends and uses
RNM_PF_TRNG_DAT and RNM_PF_TRNG_STS CSRs to read random number
and status for the applicable silicon variants.

Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>