[PATCH 01/18][PPPOE]: Introduce pppoe_hdr()

For consistency with all the other skb->nh.raw accessors.

Also do some really obvious simplifications in pppoe_recvmsg, well the
kfree_skb one is not so obvious, but free() and kfree() have the same behaviour
(hint :-) ).

Signed-off-by: Arnaldo Carvalho de Melo <redacted>
---
 drivers/net/pppoe.c      |   22 ++++++++--------------
 include/linux/if_pppox.h |    7 +++++++
 2 files changed, 15 insertions(+), 14 deletions(-)