x86: make generic arch support NUMAQ

... so it could fall back to normal numa and we'd reduce the impact of the
NUMAQ subarch.

NUMAQ depends on GENERICARCH
also decouple genericarch numa from acpi.
also make it fall back to bigsmp if apicid > 8.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>