The assertion checking for valid IV lengths added in 1833d6042c9a
was not properly updated to permit an IV length of 8 in commit
42dcd39528c6.
Reported by: syzbot+f0c0559b8be1d6eb28c7@syzkaller.appspotmail.com
Fixes: 42dcd39528c6 crypto: Support Chacha20-Poly1305 with a nonce size of 8 bytes.
Sponsored by: The FreeBSD Foundation