clk: add needed include and declaration to include/clk.h

This header uses ulong, so it needs to include <linux/types.h>.
Likewise, "struct udevice" must be declared before it is used.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>

include/clk.h

@@ -8,6 +8,10 @@
 #ifndef _CLK_H_
 #define _CLK_H_
 
+#include <linux/types.h>
+
+struct udevice;
+
 int soc_clk_dump(void);
 
 struct clk_ops {