wilc1000: added 'ndo_set_mac_address' callback support

Added support for 'ndo_set_mac_address call' callback to allow change of
interface MAC address.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201125114059.10006-2-ajay.kathat@microchip.com