Don't touch the shadow doorbells if it isn't necessary.
The flag could be combined into a bit mask with other
flags in a future patch.
Change-Id: I9ffd16468d29f0f0868cf849f7fece327eb6a294
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/447967
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
581e24004c