virtio-mem-pci: Fix memory leak when creating MEMORY_DEVICE_SIZE_CHANGE event

virtio-mem-pci: Fix memory leak when creating MEMORY_DEVICE_SIZE_CHANGE event

Apparently, we don't have to duplicate the string.

Fixes: 722a3c783ef4 ("virtio-pci: Send qapi events when the virtio-mem size changes")
Cc: qemu-stable@nongnu.org
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210929162445.64060-2-david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 75b98cb9f6456ccf194211beffcbf93b0a995fa4)
Signed-off-by: Michael Roth <michael.roth@amd.com>