crypto: drbg - always try to free Jitter RNG instance

The Jitter RNG is unconditionally allocated as a seed source follwoing
the patch 97f2650e

. Thus, the instance must always be deallocated.

Reported-by:  <syzbot+2e635807decef724a1fa@syzkaller.appspotmail.com>
Fixes: 97f2650e

 ("crypto: drbg - always seeded with SP800-90B ...")
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>