Adds the required flags and configuration files to enable Wi-Fi on the
HiKey960 board. The network name and password have to be set in
br-ext/board/hikey960/overlay/etc/wpa_supplicant.conf before building.
Then Wi-Fi can be enabled on the board by running 'ifup wlan0' as root.

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Acked-by: Joakim Bech <joakim.bech@linaro.org>

Adds the missing startup file to the buildroot-generated filesystem so
that networking is available in the VM as claimed by docs/qemu.md.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>