In gk20a_do_idle(), check gk20a rail status before returning. If rail is off, then only return success otherwise return failure Bug 1376916 Bug 1487804 Change-Id: I6280bf06c686b8baa4d6f49e90f47148411c3e02 Signed-off-by: Deepak Nibade <dnibade@nvidia.com> Reviewed-on: http://git-master/r/415281 Reviewed-by: Automatic_Commit_Validation_User GVS: Gerrit_Virtual_Submit Reviewed-by: Shridhar Rasal <srasal@nvidia.com> Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>