net: bridge: mst: pass vlan group directly to br_mst_vlan_set_state

Pass the already obtained vlan group pointer to br_mst_vlan_set_state()
instead of dereferencing it again. Each caller has already correctly
dereferenced it for their context. This change is required for the
following suspicious RCU dereference fix. No functional changes
intended.

Fixes: 3a7c1661

 ("net: bridge: mst: fix vlan use-after-free")
Reported-by:  <syzbot+9bbe2de1bc9d470eb5fe@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=9bbe2de1bc9d470eb5fe
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20240609103654.914987-2-razor@blackwall.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>