platform/x86:intel/pmc: Add support to show ltr_ignore value

platform/x86:intel/pmc: Add support to show ltr_ignore value

Add a column in ltr_show output to show if the IP has been ignored.
A mutex lock is used to protect the critical section as other processes
might try to write to the LTR ignore register at the same time.

Signed-off-by: Xi Pardee <xi.pardee@intel.com>
Link: https://lore.kernel.org/r/20240624203218.2428475-6-xi.pardee@linux.intel.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>