ath79: add leds migrations for archer-c7-v5
ar71xx uses `archer-c7-v5` for led prefix, but ath79 sticks to more
generic `tplink` as the DTS is reused by more boards, so we need to
perform migrations of the LED names during upgrade.
Cc: Adrian Schmutzler <[email protected]>
Signed-off-by: Petr Štetiar <[email protected]>