crypto: chtls - use after free in chtls_pt_recvmsg()

We call chtls_free_skb() but then we dereference it on the next lines.
Also "skb" can't be NULL, we just dereferenced it on the line before.

I have moved the free down a couple lines to fix this issue.

Fixes: 17a7d24a ("crypto: chtls - generic handling of data and hdr")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>