qeth use common function qeth_get_setassparms_cmd

There have been 2 identical versions of function
qeth_get_setassparms_cmd() for layer 2 and layer 3.
Remove the layer 3 function qeth_l3_get_setassparms_cmd()
and call the common one named qeth_get_setassparms_cmd()
located in qeth_core_main.c

Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: Eugene Crosser <Eugene.Crosser@ru.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>