driver-core: constify data for class_find_device()

All in-kernel users of class_find_device() don't really need mutable
data for match callback.

In two places (kernel/power/suspend_test.c, drivers/scsi/osd/osd_uld.c)
this patch changes match callbacks to use const search data.

The const is propagated to rtc_class_open() and power_supply_get_by_name()
parameters.

Note that there's a dev reference leak in suspend_test.c that's not
touched in this patch.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 199fca1..5359ca7 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -806,7 +806,7 @@
 }
 EXPORT_SYMBOL_GPL(gpio_export);
 
-static int match_export(struct device *dev, void *data)
+static int match_export(struct device *dev, const void *data)
 {
 	return dev_get_drvdata(dev) == data;
 }