ACPI: processor idle: Allow playing dead in C3 state

When some cores are disabled on AMD platforms, the system will no longer
be able to enter suspend-to-idle s0ix.

Update to allow playing dead in C3 state so that the CPUs can enter the
deepest state on AMD platforms.

BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1708
Suggested-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Richard Gong <richard.gong@amd.com>
[ rjw: Fixed coding style ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/processor_idle.c

@@ -789,7 +789,8 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 		state->enter = acpi_idle_enter;
 
 		state->flags = 0;
-		if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2) {
+		if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 ||
+		    cx->type == ACPI_STATE_C3) {
 			state->enter_dead = acpi_idle_play_dead;
 			drv->safe_state_index = count;
 		}