sh: intc: Make intc_subsys const

Now that the driver core can properly handle constant struct bus_type,
move the make intc_subsys 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>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/20240208-bus_cleanup-sh2-v1-1-729277400893@marliere.net
Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

Author: rbmarliere

drivers/sh/intc/core.c

@@ -455,7 +455,7 @@ struct syscore_ops intc_syscore_ops = {
 	.resume		= intc_resume,
 };
 
-struct bus_type intc_subsys = {
+const struct bus_type intc_subsys = {
 	.name		= "intc",
 	.dev_name	= "intc",
 };

drivers/sh/intc/internals.h

@@ -160,7 +160,7 @@ void _intc_enable(struct irq_data *data, unsigned long handle);
 /* core.c */
 extern struct list_head intc_list;
 extern raw_spinlock_t intc_big_lock;
-extern struct bus_type intc_subsys;
+extern const struct bus_type intc_subsys;
 
 unsigned int intc_get_dfl_prio_level(void);
 unsigned int intc_get_prio_level(unsigned int irq);