coresight: constify the struct device_type usage

Since commit aed65af ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the
coresight_dev_type 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>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240219-device_cleanup-coresight-v1-1-4a8a0b816183@marliere.net
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

drivers/hwtracing/coresight/coresight-priv.h

@@ -13,7 +13,7 @@
 #include <linux/pm_runtime.h>
 
 extern struct mutex coresight_mutex;
-extern struct device_type coresight_dev_type[];
+extern const struct device_type coresight_dev_type[];
 
 /*
  * Coresight management registers (0xf00-0xfcc)

drivers/hwtracing/coresight/coresight-sysfs.c

@@ -377,7 +377,7 @@ static struct attribute *coresight_source_attrs[] = {
 };
 ATTRIBUTE_GROUPS(coresight_source);
 
-struct device_type coresight_dev_type[] = {
+const struct device_type coresight_dev_type[] = {
 	[CORESIGHT_DEV_TYPE_SINK] = {
 		.name = "sink",
 		.groups = coresight_sink_groups,