crypto: ansi_cprng - Fix module initialization

Return the value we got from crypto_register_alg() instead of
returning 0 in any case.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>