ACPI: button: Add a debug message when we're sending a LID event

I've been debugging some spurious suspend issues on various devices,
at least on some devices these spurious suspends are caused by surious
LID closed events being send to userspace.

Running e.g. evemu-record after noticing a spurious suspend is too late
to detect that a LID closed event it the (probable) cause of this.

This commit adds an acpi_handle_debug call to help debugging this.

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