kobject: unexport kobject_create() in kobject.h

The function kobject_create() is only used by one caller,
kobject_create_and_add(), no other driver uses it, nor is exported to
other modules.

However it's still exported in kobject.h, and can sometimes confuse
users of kobject.h.

Since all users should call kobject_create_and_add(), or if extra
attributes are needed, should alloc the memory manually then call
kobject_init_and_add().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Link: https://lore.kernel.org/r/20210831093044.110729-1-wqu@suse.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/kobject.h

@@ -101,7 +101,6 @@ int kobject_init_and_add(struct kobject *kobj,
 
 extern void kobject_del(struct kobject *kobj);
 
-extern struct kobject * __must_check kobject_create(void);
 extern struct kobject * __must_check kobject_create_and_add(const char *name,
 						struct kobject *parent);
 

lib/kobject.c

@@ -777,7 +777,7 @@ static struct kobj_type dynamic_kobj_ktype = {
  * call to kobject_put() and not kfree(), as kobject_init() has
  * already been called on this structure.
  */
-struct kobject *kobject_create(void)
+static struct kobject *kobject_create(void)
 {
 	struct kobject *kobj;