x86/intel_rdt: Introduce new "exclusive" mode

At the moment all allocations are shareable. There is no way for a user to
designate that an allocation associated with a resource group cannot be
shared by another.

Introduce the new mode "exclusive". When a resource group is marked as such
it implies that no overlap is allowed between its allocation and that of
another resource group.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/f6d24672a4280fe3b24cd2da9b5f50214439c1af.1529706536.git.reinette.chatre@intel.com