ioapic: Fix error handling in realize()

Calling error_report() in a function that takes an Error ** argument
is suspicious.  ioapic_realize() does that, and then exit()s.
Currently mostly harmless, as the device cannot be hot-plugged.

Fixes: 20fd4b7b
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPeter Xu <peterx@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20181017082702.5581-11-armbru@redhat.com>

hw/intc/ioapic.c

@@ -21,7 +21,7 @@
  */
 
 #include "qemu/osdep.h"
-#include "qemu/error-report.h"
+#include "qapi/error.h"
 #include "monitor/monitor.h"
 #include "hw/hw.h"
 #include "hw/i386/pc.h"
@@ -393,9 +393,9 @@ static void ioapic_realize(DeviceState *dev, Error **errp)
     IOAPICCommonState *s = IOAPIC_COMMON(dev);
 
     if (s->version != 0x11 && s->version != 0x20) {
-        error_report("IOAPIC only supports version 0x11 or 0x20 "
-                     "(default: 0x%x).", IOAPIC_VER_DEF);
-        exit(1);
+        error_setg(errp, "IOAPIC only supports version 0x11 or 0x20 "
+                   "(default: 0x%x).", IOAPIC_VER_DEF);
+        return;
     }
 
     memory_region_init_io(&s->io_memory, OBJECT(s), &ioapic_io_ops, s,