console: udev: T3954: adjust rule script to new systemd-udev version
console: udev: T3954: adjust rule script to new systemd-udev version

We can no longer use bash veriable string code vor string manipulation. Move to
a more robust "cut" implementation.

vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x