crypto: caam - fix RNG init descriptor ret. code checking

When successful, the descriptor that performs RNG initialization
is allowed to return a status code of 7000_0000h, since last command
in the descriptor is a JUMP HALT.

Signed-off-by: Horia Geant? <horia.geanta@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>