vfio/display: Fix potential memleak of edid info

EDID related device region info is leaked in vfio_display_edid_init()
error path and VFIODisplay destroying path.

Fixes: 08479114b0de ("vfio/display: add edid support.")
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

hw/vfio/display.c

@@ -171,7 +171,9 @@ static void vfio_display_edid_init(VFIOPCIDevice *vdev)
 
 err:
     trace_vfio_display_edid_write_error();
+    g_free(dpy->edid_info);
     g_free(dpy->edid_regs);
+    dpy->edid_info = NULL;
     dpy->edid_regs = NULL;
     return;
 }
@@ -182,6 +184,7 @@ static void vfio_display_edid_exit(VFIODisplay *dpy)
         return;
     }
 
+    g_free(dpy->edid_info);
     g_free(dpy->edid_regs);
     g_free(dpy->edid_blob);
     timer_free(dpy->edid_link_timer);