virtio-mem: Fix the iterator variable in a vmem->rdl_list loop

It should be the variable rdl2 to revert the already-notified listeners.

Fixes: 2044969 ("virtio-mem: Implement RamDiscardManager interface")
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Message-Id: <20221228090312.17276-1-chenyi.qiang@intel.com>
Cc: qemu-stable@nongnu.org
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
(cherry picked from commit 29f1b32)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

hw/virtio/virtio-mem.c

@@ -341,7 +341,7 @@ static int virtio_mem_notify_plug(VirtIOMEM *vmem, uint64_t offset,
     if (ret) {
         /* Notify all already-notified listeners. */
         QLIST_FOREACH(rdl2, &vmem->rdl_list, next) {
-            MemoryRegionSection tmp = *rdl->section;
+            MemoryRegionSection tmp = *rdl2->section;
 
             if (rdl2 == rdl) {
                 break;