There's no need to get the length of an DT array property before
parsing the array. of_property_read_variable_u8_array() takes a minimum
and maximum length and returns the actual length (or error code).

This is part of a larger effort to remove callers of of_get_property()
and similar functions. of_get_property() leaks the DT property data
pointer which is a problem for dynamically allocated nodes which may
be freed.
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240731201407.1838385-4-robh@kernel.org