clk: Drop dm.h header file in clk-provider.h

This header file should not be included in other header files. Remove it
and use a forward declaration and un-inlining of dev_get_clk_ptr()
instead.

Fix up the kendryte header files to avoid build errors.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
index 15656f5..934cd57 100644
--- a/drivers/clk/clk-uclass.c
+++ b/drivers/clk/clk-uclass.c
@@ -25,6 +25,11 @@
 	return (const struct clk_ops *)dev->driver->ops;
 }
 
+struct clk *dev_get_clk_ptr(struct udevice *dev)
+{
+	return (struct clk *)dev_get_uclass_priv(dev);
+}
+
 #if CONFIG_IS_ENABLED(OF_CONTROL)
 # if CONFIG_IS_ENABLED(OF_PLATDATA)
 int clk_get_by_driver_info(struct udevice *dev, struct phandle_1_arg *cells,