hw/arm: Express dependencies of the highbank machines with Kconfig

Add Kconfig dependencies for the highbank machine (and the midway
machine).
This patch is slightly based on earlier work by Ákos Kovács (i.e.
his "hw/arm/Kconfig: Add ARM Kconfig" patch).

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2 files changed