Troubleshooting mode (syslinux): stop passing options that can only break stuff

With "nomodeset", GDM disables Wayland, but we only support Wayland, so this cannot possibly work.

And I don't think vga=normal (which is about old-school video framebuffer) is going to help a DRM driver set up graphics.

Part of Troubleshooting mode: stop passing options that... (tails!999 - merged)