hw/riscv: allow ramfb on virt

Allow ramfb on virt.  This lets `-device ramfb' work.

Signed-off-by: Asherah Connor <ashe@kivikakk.ee>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20210318235041.17175-3-ashe@kivikakk.ee
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index e96ec4c..c0dc69f 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -42,6 +42,7 @@
 #include "sysemu/sysemu.h"
 #include "hw/pci/pci.h"
 #include "hw/pci-host/gpex.h"
+#include "hw/display/ramfb.h"
 
 static const MemMapEntry virt_memmap[] = {
     [VIRT_DEBUG] =       {        0x0,         0x100 },
@@ -781,6 +782,8 @@
     mc->cpu_index_to_instance_props = riscv_numa_cpu_index_to_props;
     mc->get_default_cpu_node_id = riscv_numa_get_default_cpu_node_id;
     mc->numa_mem_supported = true;
+
+    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_RAMFB_DEVICE);
 }
 
 static const TypeInfo virt_machine_typeinfo = {