acpi: thermal: display forced passive trip points in proc

Users can force a passive trip point for a thermal zone that does not have
_PSV defined in ACPI by setting the passive attribute in sysfs.  It's
useful to display such trip points in /proc/acpi/thermal_zone.

.../TZ1/cooling_mode:<setting not supported>
.../TZ1/polling_frequency:polling frequency:       10 seconds
.../TZ1/state:state:                   ok
.../TZ1/temperature:temperature:             53 C
.../TZ1/trip_points:critical (S5):           110 C
.../TZ1/trip_points:passive (forced):        95 C

And if not set (passive is 0):
.../TZ1/trip_points:passive (forced):<not set>
Signed-off-by: Frans Pop <elendil@planet.nl>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/thermal.c

@@ -1052,6 +1052,13 @@ static int acpi_thermal_trip_seq_show(struct seq_file *seq, void *offset)
 				   acpi_device_bid(device));
 		}
 		seq_puts(seq, "\n");
+	} else {
+		seq_printf(seq, "passive (forced):");
+		if (tz->thermal_zone->forced_passive)
+			seq_printf(seq, "        %i C\n",
+				   tz->thermal_zone->forced_passive / 1000);
+		else
+			seq_printf(seq, "<not set>\n");
 	}
 
 	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++) {