hwmon: (pwm-fan) Convert to use of_property_read_u32_array()

hwmon: (pwm-fan) Convert to use of_property_read_u32_array()

This is a preparatory change to fulfill further conversion
the driver to be OF-independent. The independent code has
no analogue API that can read the value by index in the device
property array.

Suggested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240404191323.3547465-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>