remoteproc: Make rproc_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 rproc_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://lore.kernel.org/r/20240305-class_cleanup-remoteproc2-v1-1-1b139e9828c9@marliere.netSigned-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

drivers/remoteproc/remoteproc_internal.h

@@ -72,7 +72,7 @@ void rproc_init_debugfs(void);
 void rproc_exit_debugfs(void);
 
 /* from remoteproc_sysfs.c */
-extern struct class rproc_class;
+extern const struct class rproc_class;
 int rproc_init_sysfs(void);
 void rproc_exit_sysfs(void);
 

drivers/remoteproc/remoteproc_sysfs.c

@@ -254,7 +254,7 @@ static const struct attribute_group *rproc_devgroups[] = {
 	NULL
 };
 
-struct class rproc_class = {
+const struct class rproc_class = {
 	.name		= "remoteproc",
 	.dev_groups	= rproc_devgroups,
 };