The skb_reserve call prior to DMA mapping the RX skb reduced the skb
data len by 2. To not allow DMA to write behind the skb we should pass
the correct skb data len to the device.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@24123 3c298f89-4303-0410-b956-a3cf2f4a3e73