Mounting VFat drive yields error messages.

Mounting a virtual Fat drive results in error messages (see attached image). 

* https://www.qemu.org/docs/master/system/images.html#virtual-fat-disk-images

The "drive" is however mounted, and as a test, saving a text file to the drive is successfully stored in the directory `/tmp`, which can be read after shutdown of Qemu.

    Archlinux 5.9.11-arch2-1 (64-bit)
    qemu-headless 5.1.0-3
  
    qemu-system-x86_64 -boot order=d -name test \
      -enable-kvm -m 2G -cpu host -k sv \
      -daemonize \
      -drive if=pflash,format=raw,readonly,file=/usr/share/edk2-ovmf/x64/OVMF_CODE.fd \
      -drive if=pflash,format=raw,file=~/vm/OVMF_VARS.local.fd \
      -drive if=ide,format=raw,media=disk,index=1,file=fat:rw:/tmp \
      -vnc :1 \
      -cdrom /obj/archlinux/release/2020.10.01-x86_64.iso \
      -drive format=raw,index=0,media=disk,file=~/vm/qemu.raw