Add checking for valid magic values (needed for stability in the event
corrupted packets are received) and remove some other unneeded checks.
Also, fix flagging device as WWAN (Bugzilla bug #39952).
Signed-off-by: NMark Kamichoff <prox@prolixium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>