Wifi protocol needs extra checks

[DrBomb]

Referring to this comment in ESP-IDF espressif/esp-idf#702 (comment)

The comment means that only the following options are valid:

WIFI_PROTOCOL_11B
WIFI_PROTOCOL_11B | WIFI_PROTOCOL_11G
WIFI_PROTOCOL_11B | WIFI_PROTOCOL_11G | WIFI_PROTOCOL_11N

Can verify that by setting protocol to just G or GN or N the device will fail to boot with esp32_wifi.c:496 Failed to set AP protocol: ESP_ERR_INVALID_ARG

Mode LR can be the only protocol on the argument.