usb: dwc3: Use of_property_read_variable_u32_array() to read "power"

usb: dwc3: Use of_property_read_variable_u32_array() to read "power"

There's no need to get the length of an DT array property before
parsing the array. of_property_read_variable_u32_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_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.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20240731201407.1838385-5-robh@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>