platform/x86:intel/pmc: Add support to undo ltr_ignore

platform/x86:intel/pmc: Add support to undo ltr_ignore

Add ltr_restore support to undo the ltr_ignore action. It sets the
ltr_ignore bit of the corresponding IP to 0. Ltr_restore reuses some
functionality of pmc_core_ltr_ignore_write() so moved the common
functionality into a helper function.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
Link: https://lore.kernel.org/r/20240624203218.2428475-10-xi.pardee@linux.intel.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>