Staging: iio: adt7316: Move symbol export to definition

This patch clears the following checkpatch.pl warning:

WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable
+EXPORT_SYMBOL_GPL(adt7316_pm_ops);

Signed-off-by: David Veenstra <davidjulianveenstra@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>