[PPP] pppoe: Fix skb_unshare_check call position

The skb_unshare_check call needs to be made before pskb_may_pull,
not after.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed