remoteproc: qcom: q6v5-mss: add SCM probe dependency

The memory ownership transfer request is performed using SCM, ensure
that SCM is available before we probe the driver if memory protection is
needed by the subsystem.

Fixes: 6c5a9dc2 ("remoteproc: qcom: Make secure world call for mem ownership switch")
Cc: stable@vger.kernel.org
Signed-off-by: Brian Norris <briannorris@chromium.org>
[bjorn: Added condition for need_mem_protection, updated commit message]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/qcom_q6v5_mss.c

@@ -1152,6 +1152,9 @@ static int q6v5_probe(struct platform_device *pdev)
 	if (!desc)
 		return -EINVAL;
 
+	if (desc->need_mem_protection && !qcom_scm_is_available())
+		return -EPROBE_DEFER;
+
 	rproc = rproc_alloc(&pdev->dev, pdev->name, &q6v5_ops,
 			    desc->hexagon_mba_image, sizeof(*qproc));
 	if (!rproc) {