klipper-flash: fix build

Otherwise the build fails with:

> SC2068 (error): Double quote array expansions to avoid re-splitting elements.

Changed files
+1 -1
pkgs
servers
+1 -1
pkgs/servers/klipper/klipper-flash.nix
···
if matchBoard != null && matchPlatform != null then
''
pushd ${klipper-firmware}
-
${klipper}/lib/scripts/flash_usb.py -t ${matchBoard} -d ${flashDevice} ${klipper-firmware}/klipper.bin $@
+
${klipper}/lib/scripts/flash_usb.py -t ${matchBoard} -d ${flashDevice} ${klipper-firmware}/klipper.bin "$@"
popd
''
else