iio:dac:ad5592r: Move exports into IIO_AD5592R namespace

In order to avoid unnecessary pollution of the global symbol namespace
move the common/library functions into a specific namespace and import
that into the various specific device drivers that use them.

For more information see https://lwn.net/Articles/760045/

Signed-off-by: Jonathan Cameron <[e-mail]>
Cc: Paul Cercueil <[e-mail]>
Reviewed-by: Paul Cercueil <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/iio/dac/ad5592r-base.c

···
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(ad5592r_probe);
+EXPORT_SYMBOL_NS_GPL(ad5592r_probe, IIO_AD5592R);
 
 void ad5592r_remove(struct device *dev)
 {
···
 	if (st->reg)
 		regulator_disable(st->reg);
 }
-EXPORT_SYMBOL_GPL(ad5592r_remove);
+EXPORT_SYMBOL_NS_GPL(ad5592r_remove, IIO_AD5592R);
 
 MODULE_AUTHOR("Paul Cercueil <[e-mail]>");
 MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");

drivers/iio/dac/ad5592r.c

···
 MODULE_AUTHOR("Paul Cercueil <[e-mail]>");
 MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
 MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(IIO_AD5592R);

drivers/iio/dac/ad5593r.c

···
 MODULE_AUTHOR("Paul Cercueil <[e-mail]>");
 MODULE_DESCRIPTION("Analog Devices AD5593R multi-channel converters");
 MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(IIO_AD5592R);