of: unittest: Use of_property_present()

of: unittest: Use of_property_present()

Use of_property_present() to test for property presence rather than
of_find_property(). This is part of a larger effort to remove callers
of of_find_property() and similar functions. of_find_property() leaks
the DT struct property and data pointers which is a problem for
dynamically allocated nodes which may be freed.

Link: https://lore.kernel.org/r/20240731191312.1710417-10-robh@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>