crypto: rng - Convert low-level crypto_rng to new style

crypto: rng - Convert low-level crypto_rng to new style

Orabug: 26330509

This patch converts the low-level crypto_rng interface to the
"new" style.

This allows existing implementations to be converted over one-
by-one.  Once that is complete we can then remove the old rng
interface.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
(cherry picked from commit acec27ff35af9caf34d76d16ee17ff3b292e7d83)
Signed-off-by: Somasundaram Krishnasamy <somasundaram.krishnasamy@oracle.com>
Reviewed-by: Jack Vogel <jack.vogel@oracle.com>