iio: accel: mma8452: Switch from of specific to fwnode property handling.

In this case only use was to get an irq so easily converted.
Also include linux/mod_devicetable.h for struct of_device_id definition.

Using the generic firmware handling, this driver may be used with other
firmware types. This also removes an example that might get copied into
other drivers leaving them unable to be used with alternative firmware
types.

Cc: Haibo Chen <haibo.chen@nxp.com>
Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240218172731.1023367-7-jic23@kernel.org


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>