Move the target_disas() sparc specifics to the QOM disas_set_info hook
and delete the #ifdef specific code in disas.c.

Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>