x86/resctrl: Display RMID of resource group

In x86, hardware uses RMID to identify a monitoring group. When a user
creates a monitor group these details are not visible. These details
can help resctrl debugging.

Add RMID(mon_hw_id) to the monitor groups display in the resctrl interface.
Users can see these details when resctrl is mounted with "-o debug" option.

Add RFTYPE_MON_BASE that complements existing RFTYPE_CTRL_BASE and
represents files belonging to monitoring groups.

Other architectures do not use "RMID". Use the name mon_hw_id to refer
to "RMID" in an effort to keep the naming generic.

For example:
  $cat /sys/fs/resctrl/mon_groups/mon_grp1/mon_hw_id
  3

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-10-babu.moger@amd.com