nvme: explicitly set non-error for directives

Stream directives is an optional feature. It is not an error if a
controller doesn't support as many as the kernel can optionally use.
Explicitly set the non-error return value on this condition with a
comment explaining why.

Note, the return value was already 0 in this condition, so the setting
is redundant. This patch should just silence bots that falsely believe
the condition contains an error omission.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

drivers/nvme/host/core.c

@@ -809,6 +809,8 @@ static int nvme_configure_directives(struct nvme_ctrl *ctrl)
 	if (ctrl->nssa < BLK_MAX_WRITE_HINTS - 1) {
 		dev_info(ctrl->device, "too few streams (%u) available\n",
 					ctrl->nssa);
+		/* this condition is not an error: streams are optional */
+		ret = 0;
 		goto out_disable_stream;
 	}