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

Changed files
+1
nixos
modules
system
+1
nixos/modules/system/boot/systemd.nix
···
"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"