libvhost-user: Don't search for duplicates when removing memory regions

We cannot have duplicate memory regions, something would be deeply
flawed elsewhere. Let's just stop the search once we found an entry.

We'll add more sanity checks when adding memory regions later.

Reviewed-by: Raphael Norwitz <raphael@enfabrica.net>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20240214151701.29906-9-david@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

subprojects/libvhost-user/libvhost-user.c

@@ -896,8 +896,7 @@ vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
             i--;
 
             found = true;
-
-            /* Continue the search for eventual duplicates. */
+            break;
         }
     }