arm64: dts: mt7622: add ePA/eLNA pinmux for built-in WiFi

This just illustrates one of possible combinations. User should setup
the corresponding pins according to the onboard RF data that stores
in eeprom.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Link: https://lore.kernel.org/r/641c5e40f54e7c9c8eaa6be398d7169445b6fede.1617006498.git.ryder.lee@mediatek.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>