ACPI: EC: Remove duplicate ThinkPad X1 Carbon 6th entry from DMI quirks

Somehow the "ThinkPad X1 Carbon 6th" entry ended up twice in the
struct dmi_system_id acpi_ec_no_wakeup[] array. Remove one of
the entries.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>