clk: mediatek: Properly include clk.h

We don't need to include clk.h in header files, just forward
declare struct clk here. This leads us to a few places where the
include of clk.h was missing in C files. Add them.

Cc: James Liao <[e-mail]>
Cc: Henry Chen <[e-mail]>
Cc: Sascha Hauer <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/mediatek/clk-gate.h

···
 #define __DRV_CLK_GATE_H
 
 #include <linux/regmap.h>
-#include <linux/clk.h>
 #include <linux/clk-provider.h>
+
+struct clk;
 
 struct mtk_clk_gate {
 	struct clk_hw	hw;

drivers/clk/mediatek/clk-mt8135.c

···
  * GNU General Public License for more details.
  */
 
+#include <linux/clk.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/slab.h>

drivers/clk/mediatek/clk-mt8173.c

···
  * GNU General Public License for more details.
  */
 
+#include <linux/clk.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/slab.h>

drivers/clk/mediatek/clk-mtk.h

···
 
 #include <linux/regmap.h>
 #include <linux/bitops.h>
-#include <linux/clk.h>
 #include <linux/clk-provider.h>
+
+struct clk;
 
 #define MAX_MUX_GATE_BIT	31
 #define INVALID_MUX_GATE_BIT	(MAX_MUX_GATE_BIT + 1)