clk: imx8mm: fix clk set parent

Fix clk set parent, so we could still have correct clocks after
parent changing.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/drivers/clk/imx/clk-imx8mm.c b/drivers/clk/imx/clk-imx8mm.c
index 66c9601..d609fad 100644
--- a/drivers/clk/imx/clk-imx8mm.c
+++ b/drivers/clk/imx/clk-imx8mm.c
@@ -191,7 +191,10 @@
 	if (ret)
 		return ret;
 
-	return clk_set_parent(c, cp);
+	ret = clk_set_parent(c, cp);
+	c->dev->parent = cp->dev;
+
+	return ret;
 }
 
 static struct clk_ops imx8mm_clk_ops = {