mac80211: Fill in skb->protocol information for injected frames

mac80211: Fill in skb->protocol information for injected frames

Some drivers (ath9k for example) are using skb->protocol to treat EAPOL
frames somehow special (disallow aggregation for example).

When running in AP mode hostapd injects the EAPOL frames through a
monitor interface and thus skb->protocol isn't set at all. Hence, if the
injected frame is a data frame and carries a rfc1042 headaer update the
skb->protocol field accordingly.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>