ssi: Remove SSI_SLAVE_FROM_QDEV() macro

There are no usages left of this legacy cast. Delete.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
[AF: Rename SSISlave parent field]
Signed-off-by: Andreas Färber <afaerber@suse.de>

ssi: Rename parent field

include/hw/ssi.h

@@ -56,13 +56,12 @@ typedef struct SSISlaveClass {
 } SSISlaveClass;
 
 struct SSISlave {
-    DeviceState qdev;
+    DeviceState parent_obj;
 
     /* Chip select state */
     bool cs;
 };
 
-#define SSI_SLAVE_FROM_QDEV(dev) DO_UPCAST(SSISlave, qdev, dev)
 #define FROM_SSI_SLAVE(type, dev) DO_UPCAST(type, ssidev, dev)
 
 extern const VMStateDescription vmstate_ssi_slave;