mailbox: fix gce_num of mt8192 driver data

Because mt8192 only have 1 gce, the gce_num should be 1.

Fixes: 85dfdbfc ("mailbox: cmdq: add multi-gce clocks support for mt8195")
Signed-off-by: Njason-jh.lin <jason-jh.lin@mediatek.com>
Reviewed-by: NMatthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: NJassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/mtk-cmdq-mailbox.c

@@ -658,7 +658,7 @@ static const struct gce_plat gce_plat_v5 = {
 	.thread_nr = 24,
 	.shift = 3,
 	.control_by_sw = true,
-	.gce_num = 2
+	.gce_num = 1
 };
 
 static const struct gce_plat gce_plat_v6 = {