staging: wilc1000: remove use of 'src_addr' element in 'wilc_vif' struct

Remove use of 'src_addr' element in wilc_vif, as the same information
already copied to net_device->dev_addr.

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