qemu: remove unnecessary '-serial none' arg

When not using the --graphics mode, or without the script options, QEmu
was always launched with:

  -serial none -serial chardev:console

'-serial none' means "don't allocate this serial device". Here, it is
directly overridden by another serial. Best not to declare '-serial none'
then.

Since QEmu 8.2.2, having '-serial none -serial <something>' is no longer
supported, and it is then recommended to remove the unnecessary '-serial
none' [1]. It continues to work on previous versions (tested on 8.2.1).

Reported-by: @tehcaster
Closes: #97
Link: https://lore.kernel.org/qemu-devel/20240122163607.459769-2-peter.maydell@linaro.org/ [1]
Suggested-by: @ishitatsuyuki
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

virtme/commands/run.py

@@ -1001,7 +1001,6 @@ def do_it() -> int:
 
     if args.graphics is None and not args.script_sh and not args.script_exec:
         qemuargs.extend(["-echr", "1"])
-        qemuargs.extend(["-serial", "none"])
 
         if args.verbose:
             # Check if we have permission to access the current stderr.