mkosi: Disable lto feature of systemd spec

This makes sure the systemd spec doesn't check if LTO is working as
expected when it is actually disabled.

mkosi/mkosi.images/build/mkosi.conf.d/centos-fedora/mkosi.build.chroot

@@ -82,6 +82,7 @@ CXX_LD="$( ((LLVM)) && echo lld)" \
     --noprep \
     --build-in-place \
     --with upstream \
+    --without lto \
     $( ((WITH_TESTS)) || echo "--nocheck") \
     $( ((WITH_DOCS))  || echo "--without=docs") \
     --define "_topdir /var/tmp" \