board/lemaker/bananapro/linux-wifi.fragment: add rfkill driver into kernel by default

This fixes following error:

	# wpa_supplicant -i wlan0 -c /etc/wpa_supplicant.conf -B
	Successfully initialized wpa_supplicant
	rfkill: Cannot open RFKILL control device

Signed-off-by: Bartosz Bilas <b.bilas@grinn-global.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>