ipq40xx: re-add label MAC address for FritzBox 4040

[fblaese]

The MAC address of the GMAC is contained inside the CWMP-Account number on the label.

The label MAC address alias was defined previously, but it has been removed with the switch to IPQESS / DSA.

Restore the label MAC address alias.

Fixes: 27b441c ("ipq40xx: drop ESSEDMA + AR40xx DTS nodes")

[fblaese]

The label-mac-device alias has been removed for other devices as well.

I am not sure if it is safe to assume that the MAC address of the IPQESS gmac is identical to the ESSEDMA gmac0 (this is the case for the FritzBox 4040). I only have a FritzBox 4040 for testing purposes and I have not checked the source code of both drivers.

[hauke]

Hi @robimarko Could you please have a look at this pull request.

[robimarko]

@fblaese How are the MAC-s being set?
Since I do not see any userspace code or NVMEM cells, I suppose U-Boot is populating it via the ethernet0 alias.
If it's being set via the ethernet0 alias then the old gmac0 will match gmac here.

Was this runtime tested to produce the MAC matching the label(It looks like it should)

[fblaese]

That is a good question. I haven't looked into this, but the mac address is indeed correct, so I assume it is set up by uboot if the driver does not do it.

This change is run-tested for the FritzBox 4040.

If it is safe to assume that the old gmac0 is equivalent to gmac in this regard, the mac-label-devices should probably be restored for all devices which previously had it.

[robimarko]

That is a safe assumption in most cases but not always.
For the PR:
Reviewed-by: Robert Marko <robimarko@gmail.com>