hw/intc/spapr_xive: Do not use SysBus API to map local MMIO region

There is no point in exposing an internal MMIO region via
SysBus and directly mapping it in the very same device.

Just map it without using the SysBus API.

Transformation done using the following coccinelle script:

  @@
  expression sbdev;
  expression index;
  expression addr;
  expression subregion;
  @@
  -    sysbus_init_mmio(sbdev, subregion);
       ... when != sbdev
  -    sysbus_mmio_map(sbdev, index, addr);
  +    memory_region_add_subregion(get_system_memory(), addr, subregion);

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20231019131647.19690-8-philmd@linaro.org>

hw/intc/spapr_xive.c

@@ -350,12 +350,12 @@ static void spapr_xive_realize(DeviceState *dev, Error **errp)
      * Map all regions. These will be enabled or disabled at reset and
      * can also be overridden by KVM memory regions if active
      */
-    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xsrc->esb_mmio);
-    sysbus_mmio_map(SYS_BUS_DEVICE(xive), 0, xive->vc_base);
-    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &end_xsrc->esb_mmio);
-    sysbus_mmio_map(SYS_BUS_DEVICE(xive), 1, xive->end_base);
-    sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xive->tm_mmio);
-    sysbus_mmio_map(SYS_BUS_DEVICE(xive), 2, xive->tm_base);
+    memory_region_add_subregion(get_system_memory(), xive->vc_base,
+                                &xsrc->esb_mmio);
+    memory_region_add_subregion(get_system_memory(), xive->end_base,
+                                &end_xsrc->esb_mmio);
+    memory_region_add_subregion(get_system_memory(), xive->tm_base,
+                                &xive->tm_mmio);
 }
 
 static int spapr_xive_get_eas(XiveRouter *xrtr, uint8_t eas_blk,