staging: wilc1000: fix to set correct value for 'vif_num'

commit dda037057a572f5c82ac2499eb4e6fb17600ba3e upstream.

Set correct value in '->vif_num' for the total number of interfaces and
set '->idx' value using 'i'.

Fixes: 735bb39c ("staging: wilc1000: simplify vif[i]->ndev accesses")
Fixes: 0e490657 ("staging: wilc1000: Fix problem with wrong vif index")
Cc: <stable@vger.kernel.org>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>