wilc1000: remove redundant assignment to pointer vif

The assignment to pointer vif is redundant as the assigned value
is never read, hence it can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201203174316.1071446-1-colin.king@canonical.com