nvml/bw: add nvlink versions 3&4

Possible version values aren't documented in NVML API doc,
but wikipedia and other sources say 50GB/s per link
for v3 (Ampere) and v4 (Hopper).

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>

hwloc/topology-nvml.c

@@ -357,6 +357,8 @@ hwloc_nvml_discover(struct hwloc_backend *backend, struct hwloc_disc_status *dst
           bw = 20000; /* multiple links may connect same GPUs */
         } else if (version == 2) {
           bw = 25000; /* multiple links may connect same GPUs */
+        } else if (version == 3 || version == 4) {
+          bw = 50000; /* multiple links may connect same GPUs */
         } else {
           static int warned = 0;
           if (!warned && HWLOC_SHOW_ALL_ERRORS())