x86: Increase CONFIG_NODES_SHIFT max to 10

Some larger systems require more than 512 nodes, so increase the
maximum CONFIG_NODES_SHIFT to 10 for a new max of 1024 nodes.

This was tested with numa=fake=64M on systems with more than
64GB of RAM. A total of 1022 nodes were initialized.

Successfully builds with no additional warnings on x86_64
allyesconfig.

( No effect on any existing config. Newly enabled CONFIG_MAXSMP=y
  will see the new default. )

Signed-off-by: David Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1003251538060.8589@chino.kir.corp.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>