Add common realize function, it is only to check validity of property.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
---
 hw/intc/loongarch_extioi.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/hw/intc/loongarch_extioi.c b/hw/intc/loongarch_extioi.c
index 039fc4dd1e..dcc278a214 100644
--- a/hw/intc/loongarch_extioi.c
+++ b/hw/intc/loongarch_extioi.c
@@ -318,14 +318,26 @@ static const MemoryRegionOps extioi_virt_ops = {
     .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
+static void loongarch_extioi_common_realize(DeviceState *dev, Error **errp)
+{
+    LoongArchExtIOICommonState *s = (LoongArchExtIOICommonState *)dev;
+
+    if (s->num_cpu == 0) {
+        error_setg(errp, "num-cpu must be at least 1");
+        return;
+    }
+}
+
 static void loongarch_extioi_realize(DeviceState *dev, Error **errp)
 {
     LoongArchExtIOI *s = LOONGARCH_EXTIOI(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    Error *local_err = NULL;
     int i, pin;
 
-    if (s->num_cpu == 0) {
-        error_setg(errp, "num-cpu must be at least 1");
+    loongarch_extioi_common_realize(dev, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
         return;
     }
 
-- 
2.43.5