Make use of fifo8 functions instead of implementing own fifo code.
This makes the code more readable and reduces risk of bugs.

Signed-off-by: Arwed Meyer <arwed.meyer@gmx.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220911181840.8933-4-arwed.meyer@gmx.de>