Input: synaptics-rmi4 - make rmi_bus_type const

Now that the driver core can properly handle constant struct bus_type,
move the variable rmi_bus_type to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Suggested-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Ricardo B. Marliere <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/rmi4/rmi_bus.c

···
 	return physical || rmi_function_match(dev, drv);
 }
 
-struct bus_type rmi_bus_type = {
+const struct bus_type rmi_bus_type = {
 	.match		= rmi_bus_match,
 	.name		= "rmi4",
 };

drivers/input/rmi4/rmi_bus.h

···
 
 int rmi_for_each_dev(void *data, int (*func)(struct device *dev, void *data));
 
-extern struct bus_type rmi_bus_type;
+extern const struct bus_type rmi_bus_type;
 
 int rmi_of_property_read_u32(struct device *dev, u32 *result,
 				const char *prop, bool optional);