At present, vif->idx is assigned the value of wl->vif_num
at the beginning of this block and device is initialized
based on this index value.
In the next iteration, wl->vif_num is still 0 as it is only updated
later but gets assigned to vif->idx in the beginning. This causes problems
later when we try to reference a particular interface and also while
configuring the firmware.
This patch moves the assignment to vif->idx from the beginning
of the block to after wl->vif_num is updated with latest value of i.