phy: rockchip-emmc: should be a child device of the GRF

The emmc-phy is fully enclosed in the general register files (GRF).
Therefore as seen from the device-tree it shouldn't be a separate platform-
device but instead a sub-device of the GRF - using the simply-mfd mechanism.

The driver entered the kernel in the current merge-window, so we can still
adapt the binding without needing a fallback, as the binding hasn't been
released with a full kernel yet.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/phy-rockchip-emmc.c

@@ -176,7 +176,10 @@ static int rockchip_emmc_phy_probe(struct platform_device *pdev)
 	struct regmap *grf;
 	unsigned int reg_offset;
 
-	grf = syscon_regmap_lookup_by_phandle(dev->of_node, "rockchip,grf");
+	if (!dev->parent || !dev->parent->of_node)
+		return -ENODEV;
+
+	grf = syscon_node_to_regmap(dev->parent->of_node);
 	if (IS_ERR(grf)) {
 		dev_err(dev, "Missing rockchip,grf property\n");
 		return PTR_ERR(grf);