[NET]: Correct two mistaken skb_reset_mac_header() conversions.

This operation helper abstracts:

	skb->mac_header = skb->data;

but it was done in two more places which were actually:

	skb->mac_header = skb->network_header;

and those are corrected here.

Signed-off-by: David S. Miller <davem@davemloft.net>