fs/resctrl: Introduce counter ID read, reset calls in mbm_event mode

fs/resctrl: Introduce counter ID read, reset calls in mbm_event mode

When supported, "mbm_event" counter assignment mode allows users to assign
a hardware counter to an RMID, event pair and monitor the bandwidth usage as
long as it is assigned. The hardware continues to track the assigned counter
until it is explicitly unassigned by the user.

Introduce the architecture calls resctrl_arch_cntr_read() and
resctrl_arch_reset_cntr() to read and reset event counters when "mbm_event"
mode is supported. Function names match existing resctrl_arch_rmid_read() and
resctrl_arch_reset_rmid().

Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com