config: disable CONFIG_SYSFB_SIMPLEFB
    
    The new option in 5.15 is a rename from CONFIG_X86_SYSFB which we had disabled
    due to bsc#855821. Moreover, enabling CONFIG_SYSFB_SIMPLEFB caused regression
    on my UEFI desktop - no printk output on screen between grub's loading of
    kernel and initrd, and a gpu modesetting driver taking over.