6lowpan: reassembly: fix access of ctl table entry

Correct offset is 3 of the 6lowpanfrag_max_datagram_size value in proc
entry ctl table and not 2.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed