ipq40xx: Lyra: update RGB LED-Controller node for 5.10+

ipq40xx: Lyra: update RGB LED-Controller node for 5.10+

Add the reg and color property to each channel node. This
update is to accommodate the multicolor framework.

Refer to:
<https://lore.kernel.org/all/20200622185919[email protected]>
<https://lore.kernel.org/all/20210818070209.1540451[email protected]>

Note:

There is only a single extremely bright RGB-LED.
The RGB-color channels (i.e.: blue-0, blue-1 and blue-2)
are running in parallel to increase the current delivery
beyond what a single PWM-output on the LED controller
could do.

BugLink: https://github.com/openwrt/openwrt/issues/9851
Reported-By: Thomas Bøge <[email protected]>
Tested-By: Thomas Bøge <[email protected]>
Signed-off-by: Christian Lamparter <[email protected]>