qdev: Drop FROM_QBUS() macro

Use QOM cast macros I2C_BUS(), SSI_BUS(), PCI_BUS() instead.

Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/hw/ssi/ssi.c b/hw/ssi/ssi.c
index 1264d9d..2c25260 100644
--- a/hw/ssi/ssi.c
+++ b/hw/ssi/ssi.c
@@ -103,7 +103,7 @@
 {
     BusState *bus;
     bus = qbus_create(TYPE_SSI_BUS, parent, name);
-    return FROM_QBUS(SSIBus, bus);
+    return SSI_BUS(bus);
 }
 
 uint32_t ssi_transfer(SSIBus *bus, uint32_t val)