Remove serial symlink and last_rule

Cf. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=999772
and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=979538

--- a/udev-rules/64-limesuite.rules
+++ b/udev-rules/64-limesuite.rules
@@ -2,6 +2,6 @@ SUBSYSTEM=="usb", ATTR{idVendor}=="04b4"
 SUBSYSTEM=="usb", ATTR{idVendor}=="04b4", ATTR{idProduct}=="00f1", SYMLINK+="stream-%k", MODE="666"
 SUBSYSTEM=="usb", ATTR{idVendor}=="0403", ATTR{idProduct}=="601f", SYMLINK+="stream-%k", MODE="666"
 SUBSYSTEM=="usb", ATTR{idVendor}=="1d50", ATTR{idProduct}=="6108", SYMLINK+="stream-%k", MODE="666"
-SUBSYSTEM=="xillybus", MODE="666", OPTIONS="last_rule"
+SUBSYSTEM=="xillybus", MODE="666"
 
-SUBSYSTEM=="tty", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", MODE="0666", SYMLINK+="serial"
+SUBSYSTEM=="tty", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", MODE="0666"
