rockchip: Use a separate clock ID for clocks

At present we use the same peripheral ID for clocks and pinctrl. While this
works it is probably better to use the device tree clock binding ID for
clocks. We can use the clk_get_by_index() function to find this.

Update the clock drivers and the code that uses them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mmc/rockchip_dw_mmc.c b/drivers/mmc/rockchip_dw_mmc.c
index 080c831..cb9e104 100644
--- a/drivers/mmc/rockchip_dw_mmc.c
+++ b/drivers/mmc/rockchip_dw_mmc.c
@@ -20,7 +20,7 @@
 
 struct rockchip_dwmmc_priv {
 	struct udevice *clk;
-	struct rk3288_grf *grf;
+	int periph;
 	struct dwmci_host host;
 };
 
@@ -30,8 +30,7 @@
 	struct rockchip_dwmmc_priv *priv = dev_get_priv(dev);
 	int ret;
 
-	ret = clk_set_periph_rate(priv->clk, PERIPH_ID_SDMMC0 + host->dev_index,
-				  freq);
+	ret = clk_set_periph_rate(priv->clk, priv->periph, freq);
 	if (ret < 0) {
 		debug("%s: err=%d\n", __func__, ret);
 		return ret;
@@ -71,12 +70,10 @@
 	int ret;
 	int fifo_depth;
 
-	priv->grf = syscon_get_first_range(ROCKCHIP_SYSCON_GRF);
-	if (IS_ERR(priv->grf))
-		return PTR_ERR(priv->grf);
-	ret = uclass_get_device(UCLASS_CLK, CLK_GENERAL, &priv->clk);
-	if (ret)
+	ret = clk_get_by_index(dev, 0, &priv->clk);
+	if (ret < 0)
 		return ret;
+	priv->periph = ret;
 
 	if (fdtdec_get_int_array(gd->fdt_blob, dev->of_offset,
 				 "clock-freq-min-max", minmax, 2))