bpf, offload: Unlock on error in bpf_offload_dev_create()

We need to drop the bpf_devs_lock on error before returning.

Fixes: 9fd7c555 ("bpf: offload: aggregate offloads per-device")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Link: https://lore.kernel.org/bpf/20191104091536.GB31509@mwanda

kernel/bpf/offload.c

@@ -678,8 +678,10 @@ bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops, void *priv)
 	down_write(&bpf_devs_lock);
 	if (!offdevs_inited) {
 		err = rhashtable_init(&offdevs, &offdevs_params);
-		if (err)
+		if (err) {
+			up_write(&bpf_devs_lock);
 			return ERR_PTR(err);
+		}
 		offdevs_inited = true;
 	}
 	up_write(&bpf_devs_lock);