licenses.bsd3ClauseTso: rename and add spdxId

it got accepted and merged to spdx: https://github.com/spdx/license-list-XML/pull/2815

lib/licenses.nix

@@ -232,15 +232,9 @@ lib.mapAttrs mkLicense (
       fullName = "Lawrence Berkeley National Labs BSD variant license";
     };
 
-    bsd3TheodoreTso = {
-      fullName = "BSD 3 Clause Theodore Tso Variant";
-      # TODO: if the license gets accepted to spdx then
-      #   add spdxId
-      # else
-      #   remove license
-      #   && replace all references with bsd3
-      # https://tools.spdx.org/app/license_requests/442/
-      # https://github.com/spdx/license-list-XML/issues/2702
+    bsd3ClauseTso = {
+      spdxId = "BSD-3-Clause-Tso";
+      fullName = "BSD 3-Clause Tso variant";
     };
 
     bsdAxisNoDisclaimerUnmodified = {