mvebu: backport pending Turris Omnia LEDs improvements
It backports this patch series, which is currently on review:
https://lore.kernel.org/linux-leds/
20220704105955.15474-1-kabel@kernel.org/T/#rb89a4ca5a836f17bdcc53d65549e0b1779bb6a18
It allows being able to configure LEDs in userspace.
This fixes issue described in Turris Build repository
https://gitlab.nic.cz/turris/os/build/-/issues/354
It happens in OpenWrt as well.
- Before
```
root@turris:/# ls /sys/class/leds/
ath10k-phy0 ath9k-phy1 mmc0::
```
-After
```
root@turris:/# ls /sys/class/leds/
ath10k-phy0 rgb:indicator-2 rgb:lan-3 rgb:wlan-1
ath9k-phy1 rgb:lan-0 rgb:lan-4 rgb:wlan-2
mmc0:: rgb:lan-1 rgb:power rgb:wlan-3
rgb:indicator-1 rgb:lan-2 rgb:wan
```
Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>