of: Introduce and apply private is_pseudo_property()

There are several places which check if a property name is one of
'name'|'phandle'|'linux,phandle'.

Introduce and apply private is_pseudo_property() for the check.

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/r/20250224-of_bugfix-v1-2-03640ae8c3a6@quicinc.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>