crypto: drbg - fix error return code in drbg_alloc_state()

Fix to return negative error code -ENOMEM from the kzalloc error handling
case instead of 0, as done elsewhere in this function.

Reported-by: Xiumei Mu <xmu@redhat.com>
Fixes: db07cd2 ("crypto: drbg - add FIPS 140-2 CTRNG for noise source")
Cc: <stable@vger.kernel.org>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/drbg.c

@@ -1306,8 +1306,10 @@ static inline int drbg_alloc_state(struct drbg_state *drbg)
 	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
 		drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
 				     GFP_KERNEL);
-		if (!drbg->prev)
+		if (!drbg->prev) {
+			ret = -ENOMEM;
 			goto fini;
+		}
 		drbg->fips_primed = false;
 	}