sun4m: use qdev properties instead of legacy m48t59_init() function

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20201016182739.22875-3-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Hervé Poussineau <hpoussin@reactos.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>