meta-raspberrypi & meta-agl-bsp: create-combined-dtb fails

Upstream review on dtc changes may be a while: https://www.spinics.net/lists/devicetree-compiler/msg03547.html

Ok, so follow-up to make 5.4 work is to remove the cma=64M setting from the kernel cmdline.

References:

Non-working:

https://lava.automotivelinux.org/scheduler/job/15830#L2404

Working:

https://lava.automotivelinux.org/scheduler/job/15854#L2429

Forum entry:

https://www.raspberrypi.org/forums/viewtopic.php?p=1674488#p1674488

Great news, well done.

My two-line fix above turns out to break several of the dtc tests so I'm not confident in applying that to AGL. However if we modify it to only skip setting the phandle property on the target node where one already exists (preventing modification) but allow adding a phandle property where there wasn't one the tests pass. I've submitting this fix, along with a new test case, to the dts compiler mailing list.

I'll submit a change against meta-agl which adds this patch against dtc for now and we'll see how upstream respond to the patch I've submitted. That should allow us to unblock the kernel update for Raspberry Pi.

Let's eval this and then see what we can do upstream.