acpi: fix incorrect encoding for 0x{F-1}FFFF

acpi: fix incorrect encoding for 0x{F-1}FFFF

Fix typo in build_append_int() which causes integer
truncation when it's in range 0x{F-1}FFFF by packing it
as WordConst instead of required DWordConst.

In partucular this fixes a regression: hotplug in slots 16,17,18 and 19
didn't work, since SSDT had code like this:

                If (And (Arg0, 0x0000))
                {
                    Notify (S80, Arg1)
                }

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Weil <sw@weilnetz.de>