regulator: core: make regulator_class constant

Since commit 43a7206b ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the regulator_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Link: https://msgid.link/r/20240305-class_cleanup-regulator-v1-1-4950345d6d8f@marliere.netSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/core.c

@@ -5890,7 +5890,7 @@ static const struct dev_pm_ops __maybe_unused regulator_pm_ops = {
 };
 #endif
 
-struct class regulator_class = {
+const struct class regulator_class = {
 	.name = "regulator",
 	.dev_release = regulator_dev_release,
 	.dev_groups = regulator_dev_groups,

drivers/regulator/internal.h

@@ -58,7 +58,7 @@ struct regulator {
 	struct dentry *debugfs;
 };
 
-extern struct class regulator_class;
+extern const struct class regulator_class;
 
 static inline struct regulator_dev *dev_to_rdev(struct device *dev)
 {