kvmvapic: Make dependency on sysbus.h explicit

Allows kvmvapic to compile if sysbus.h is removed from apic_internal.h,
from which it is indirectly included.
sysbus.h will be removed from apic_internal.h after converting
APICs to ICCDevice.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c
index 3a10c07..5b558aa 100644
--- a/hw/i386/kvmvapic.c
+++ b/hw/i386/kvmvapic.c
@@ -12,6 +12,7 @@
 #include "sysemu/cpus.h"
 #include "sysemu/kvm.h"
 #include "hw/i386/apic_internal.h"
+#include "hw/sysbus.h"
 
 #define VAPIC_IO_PORT           0x7e