staging: wilc1000: refactor del_station() to avoid parenthesis misalignment

Refactor the code to fix open parenthesis alignment issue reported by
checkpatch.pl script in del_station().

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>