hw/cxl: Add QTG _DSM support for ACPI0017 device

hw/cxl: Add QTG _DSM support for ACPI0017 device

Add a simple _DSM call support for the ACPI0017 device to return fake QTG
ID values of 0 and 1 in all cases. This for _DSM plumbing testing from the OS.

Following edited for readability

Device (CXLM)
{
    Name (_HID, "ACPI0017")  // _HID: Hardware ID
...
    Method (_DSM, 4, Serialized)  // _DSM: Device-Specific Method
    {
        If ((Arg0 == ToUUID ("f365f9a6-a7de-4071-a66a-b40c0b4f8e52")))
        {
            If ((Arg2 == Zero))
            {
                Return (Buffer (One) { 0x01 })
            }

            If ((Arg2 == One))
            {
                Return (Package (0x02)
                {
                    One,
                    Package (0x02)
                    {
                        Zero,
                        One
                    }
                })
            }
        }
    }

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20231012125623.21101-3-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>