nixos/boot/systemd: enable tracefs (#388751)

Author: ElvishJerricco

nixos/modules/system/boot/systemd.nix

@@ -88,6 +88,7 @@ let
       "sys-fs-fuse-connections.mount"
       ] ++ (optional (!config.boot.isContainer) "sys-kernel-config.mount") ++ [
       "sys-kernel-debug.mount"
+      "sys-kernel-tracing.mount"
 
       # Maintaining state across reboots.
       "systemd-random-seed.service"