x86/intel_rdt/cqm: Clear the default RMID during hotcpu

The user configured per cpu default RMID is not cleared during cpu
hotplug. This may lead to incorrect RMID values after a cpu goes offline
and again comes back online. Clear the per cpu default RMID during cpu
offline and online handling.

Reported-by: Prakyha Sai Praneeth <sai.praneeth.prakhya@intel.com>
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Link: http://lkml.kernel.org/r/1502304395-7166-2-git-send-email-vikas.shivappa@linux.intel.com