ACPI / processor: Set default C1 idle state description

The ACPI idle driver will default to ACPI_CSTATE_HALT for C1 if a _CST
object for C1 is not defined. However, the description will not be set,
so users will see "<null>" when reading the description from sysfs.

Set the C1 state description when defaulting to ACPI_CSTATE_HALT.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index d50a7b6..226dc56 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -291,6 +291,9 @@ static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 		pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 		pr->power.states[ACPI_STATE_C1].valid = 1;
 		pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
+
+		snprintf(pr->power.states[ACPI_STATE_C1].desc,
+			 ACPI_CX_DESC_LEN, "ACPI HLT");
 	}
 	/* the C0 state only exists as a filler in our array */
 	pr->power.states[ACPI_STATE_C0].valid = 1;