dtboverlay to U-Boot runtime dtb

[Peng Fan (OSS)]

Hi,

I did a test to do overlay for U-Boot runtime dtb, but after overlay
finish, U-Boot DM driver not work properly because the of_node
pointer is changed in a device.

So I am thinking whether this is valid to overlay to runtime U-Boot
dtb or not. The reason I try this is that I wanna overlay the EFI capsule
signature to U-Boot dtb, then capsule update with authentication
could work, otherwise I need integrate the signature in dts and
rebuild the image. I understand current U-Boot not support
overlay U-Boot runtime dtb, just thinking whether this is valid or
should we support it.

Thanks,
Peng.