crypto: drbg - Fixes panic in wait_for_completion call

Initialise ctr_completion variable before use.
Signed-off-by: Harsh Jain <harshjain.prof@gmail.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/drbg.c

@@ -1691,6 +1691,7 @@ static int drbg_init_sym_kernel(struct drbg_state *drbg)
 		return PTR_ERR(sk_tfm);
 	}
 	drbg->ctr_handle = sk_tfm;
+	init_completion(&drbg->ctr_completion);
 
 	req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
 	if (!req) {