pseries: Remove old hcalls hook stub

Some time ago we removed all use of the 'hcalls' callback in the pseries
VIO code, which was used to workaround an ordering problem which has since
been solved properly.  However, the function pointer for the hook remains.
This patch cleans it away.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andreas Färber <afaerber@suse.de>

hw/spapr_vio.h

@@ -64,7 +64,6 @@ typedef struct VIOsPAPRDeviceClass {
     const char *dt_name, *dt_type, *dt_compatible;
     target_ulong signal_mask;
     int (*init)(VIOsPAPRDevice *dev);
-    void (*hcalls)(VIOsPAPRBus *bus);
     int (*devnode)(VIOsPAPRDevice *dev, void *fdt, int node_off);
 } VIOsPAPRDeviceClass;