x86/resctrl: Support Sub-NUMA cluster mode SNC6

Support Sub-NUMA cluster mode with 6 nodes per L3 cache (SNC6) on some
Intel platforms.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20241031220213.17991-1-tony.luck@intel.com