ACPI / scan: Add labels for PNP button devices

Subsequent code treats button_device_ids[] entries differently, and
it's hard to follow without a hint as to which is which.

Add comments to identify the power button, lid, and sleep button
devices.

The "PNP" prefix is owned by Microsoft, so they distribute the
canonical list of "PNP" IDs.

Link: https://uefi.org/PNP_ACPI_Registry
Link: https://download.microsoft.com/download/1/6/1/161ba512-40e2-4cc9-843a-923143f3456c/devids.txtSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/scan.c

@@ -846,9 +846,9 @@ static int acpi_bus_extract_wakeup_device_power_package(struct acpi_device *dev)
 static bool acpi_wakeup_gpe_init(struct acpi_device *device)
 {
 	static const struct acpi_device_id button_device_ids[] = {
-		{"PNP0C0C", 0},
-		{"PNP0C0D", 0},
-		{"PNP0C0E", 0},
+		{"PNP0C0C", 0},		/* Power button */
+		{"PNP0C0D", 0},		/* Lid */
+		{"PNP0C0E", 0},		/* Sleep button */
 		{"", 0},
 	};
 	struct acpi_device_wakeup *wakeup = &device->wakeup;