slimbus: core: make slimbus_bus const

Since commit d492cc25 ("driver core: device.h: make struct
bus_type a const *"), the driver core can properly handle constant
struct bus_type, move the slimbus_bus variable to be a constant
structure as well, placing it into read-only memory which can not be
modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20240224114403.86230-3-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/slimbus/core.c

@@ -100,7 +100,7 @@ static int slim_device_uevent(const struct device *dev, struct kobj_uevent_env *
 	return add_uevent_var(env, "MODALIAS=slim:%s", dev_name(&sbdev->dev));
 }
 
-struct bus_type slimbus_bus = {
+const struct bus_type slimbus_bus = {
 	.name		= "slimbus",
 	.match		= slim_device_match,
 	.probe		= slim_device_probe,

include/linux/slimbus.h

@@ -10,7 +10,7 @@
 #include <linux/completion.h>
 #include <linux/mod_devicetable.h>
 
-extern struct bus_type slimbus_bus;
+extern const struct bus_type slimbus_bus;
 
 /**
  * struct slim_eaddr - Enumeration address for a SLIMbus device