drivers/net/sb1000.c: delete double assignment

The other code around these duplicated assignments initializes the 0 1 2
and 3 elements of an array, so change the initialization of the
rx_session_id array to do the same.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/

)

// <smpl>
@@
expression i;
@@

*i = ...;
 i = ...;
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>