Factor out smbios table walking from display_uuid to smbios_next().

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
vgabios: Define PlatformRunningOn to make compile happy.

With CONFIG_COREBOOT=y, CONFIG_QEMU_HARDWARE=y, CONFIG_VGA_COREBOOT=y,
CONFIG_DEBUG_IO=y the compile would break because this variable was
missing.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
hw/pci: reserve IO and mem for pci-2-pci bridges with no devices attached

If a pci-2-pci bridge supports hot-plug functionality but there are no devices
connected to it, reserve IO/mem in order to be able to attach devices
later. Do not waste space, use minimum allowed.

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
hw/pci: check if pci2pci bridges implement optional limit registers

<I/O Base Register, I/O Limit Register> pair and
<Prefetchable Memory Base Register, Prefetchable Memory Limit Register> pair
are both optional.
Do not reserve ranges if the above registers are not implemented.

Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>