liveupdate: Remove unused ser field from struct luo_session

The ser field in struct luo_session was intended to point to the
serialized data for a session, but it was never actually utilized in the
implementation. All serialization and deserialization logic consistently
uses the pointers maintained in struct luo_session_header.

Remove the dead field to clean up the structure.

Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://patch.msgid.link/20260527202737.1345192-6-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Author: soleen

kernel/liveupdate/luo_internal.h

@@ -59,7 +59,6 @@ struct luo_file_set {
  * struct luo_session - Represents an active or incoming Live Update session.
  * @name:       A unique name for this session, used for identification and
  *              retrieval.
- * @ser:        Pointer to the serialized data for this session.
  * @list:       A list_head member used to link this session into a global list
  *              of either outgoing (to be preserved) or incoming (restored from
  *              previous kernel) sessions.
@@ -70,7 +69,6 @@ struct luo_file_set {
  */
 struct luo_session {
 	char name[LIVEUPDATE_SESSION_NAME_LENGTH];
-	struct luo_session_ser *ser;
 	struct list_head list;
 	bool retrieved;
 	struct luo_file_set file_set;