Binding for fixed NVMEM cells defined directly as NVMEM device subnodes
has been deprecated. It has been replaced by the "fixed-layout" NVMEM
layout binding.
New syntax is meant to be clearer and should help avoiding imprecise
bindings.
NVMEM subsystem already supports the new binding. It should be a good
idea to limit support for old syntax to existing drivers that actually
support & use it (we can't break backward compatibility!). That way we
additionally encourage new bindings & drivers to ignore deprecated
binding.
It wasn't clear (to me) if rtc and w1 code actually uses old syntax
fixed cells. I enabled them to don't risk any breakage.