habanalabs: add debug print when rejecting CS

When rejecting CS because of too many in-flight CS, print a debug message
about it as it useful to know when the user is debugging (it indicates a
back-pressure from the driver as the device is not fast enough to consume
the CS)
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Reviewed-by: Omer Shpigelman <oshpigelman@habana.ai>

drivers/misc/habanalabs/command_submission.c

@@ -305,6 +305,8 @@ static int allocate_cs(struct hl_device *hdev, struct hl_ctx *ctx,
 	other = ctx->cs_pending[fence->cs_seq & (HL_MAX_PENDING_CS - 1)];
 	if ((other) && (!dma_fence_is_signaled(other))) {
 		spin_unlock(&ctx->cs_lock);
+		dev_dbg(hdev->dev,
+			"Rejecting CS because of too many in-flights CS\n");
 		rc = -EAGAIN;
 		goto free_fence;
 	}