mailbox: mtk-cmdq: Validate alias_id on probe

of_alias_get_id() may return -ENODEV which leads to illegal access to
the cmdq->clocks array.
Adding a check over alias_id to prevent the unexpected behavior.

Fixes: 85dfdbfc13 ("mailbox: cmdq: add multi-gce clocks support for mt8195")
Signed-off-by: Fei Shao <fshao@chromium.org>
Reviewed-by: Tzung-Bi Shih <tzungbi@google.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/mtk-cmdq-mailbox.c

@@ -570,7 +570,7 @@ static int cmdq_probe(struct platform_device *pdev)
 			char clk_id[8];
 
 			alias_id = of_alias_get_id(node, clk_name);
-			if (alias_id < cmdq->gce_num) {
+			if (alias_id >= 0 && alias_id < cmdq->gce_num) {
 				snprintf(clk_id, sizeof(clk_id), "%s%d", clk_name, alias_id);
 				cmdq->clocks[alias_id].id = clk_id;
 				cmdq->clocks[alias_id].clk = of_clk_get(node, 0);