crypto: caam - fix smatch warnings

Fix the following smatch warnings:

drivers/crypto/caam/caamalg.c:2350 aead_edesc_alloc() warn: we tested 'src_nents' before and it was 'true'
drivers/crypto/caam/caamrng.c:351 caam_rng_init() error: no modifiers for allocation.

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