printk: kmsg_dump: remove unused fields

struct kmsg_dumper still contains some fields that were used to
iterate the old ringbuffer. They are no longer used. Remove them
and update the struct documentation.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-5-john.ogness@linutronix.de

include/linux/kmsg_dump.h

@@ -36,6 +36,9 @@ enum kmsg_dump_reason {
  * 		through the record iterator
  * @max_reason:	filter for highest reason number that should be dumped
  * @registered:	Flag that specifies if this is already registered
+ * @active:	Flag that specifies if this is currently dumping
+ * @cur_seq:	Points to the oldest message to dump
+ * @next_seq:	Points after the newest message to dump
  */
 struct kmsg_dumper {
 	struct list_head list;
@@ -45,8 +48,6 @@ struct kmsg_dumper {
 	bool registered;
 
 	/* private state of the kmsg iterator */
-	u32 cur_idx;
-	u32 next_idx;
 	u64 cur_seq;
 	u64 next_seq;
 };