usb: clarify ACPI spec version and section number for _UPC & _PLD

ACPI spec inserts sections for new features frequently and section
numbers are changed. It is easy to refer to ACPI spec if ACPI version
is available in comments.

There are no functional changes.
Signed-off-by: NAlex Hung <alex.hung@canonical.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/usb-acpi.c

@@ -90,8 +90,8 @@ static enum usb_port_connect_type usb_acpi_get_connect_type(acpi_handle handle,
 	acpi_status status;
 
 	/*
-	 * According to ACPI Spec 9.13. PLD indicates whether usb port is
-	 * user visible and _UPC indicates whether it is connectable. If
+	 * According to 9.14 in ACPI Spec 6.2. _PLD indicates whether usb port
+	 * is user visible and _UPC indicates whether it is connectable. If
 	 * the port was visible and connectable, it could be freely connected
 	 * and disconnected with USB devices. If no visible and connectable,
 	 * a usb device is directly hard-wired to the port. If no visible and