rockchip: mmc: dm: convert fdt_get to dev_read

With the new dev_read functions available, we can convert the rockchip
architecture-specific drivers and common drivers used by these devices
over to the dev_read family of calls.

This covers the dw_mmc and sdhci wrapper drivers for Rockchip.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mmc/rockchip_sdhci.c b/drivers/mmc/rockchip_sdhci.c
index 8985878..f31d329 100644
--- a/drivers/mmc/rockchip_sdhci.c
+++ b/drivers/mmc/rockchip_sdhci.c
@@ -50,8 +50,7 @@
 	max_frequency = dtplat->max_frequency;
 	ret = clk_get_by_index_platdata(dev, 0, dtplat->clocks, &clk);
 #else
-	max_frequency = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
-			"max-frequency", 0);
+	max_frequency = dev_read_u32_default(dev, "max-frequency", 0);
 	ret = clk_get_by_index(dev, 0, &clk);
 #endif
 	if (!ret) {