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 <jamesjj.liao@mediatek.com>
Cc: Henry Chen <henryc.chen@mediatek.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/drivers/clk/mediatek/clk-mt8173.c b/drivers/clk/mediatek/clk-mt8173.c
index 4b9e04c..2e0f17b 100644
--- a/drivers/clk/mediatek/clk-mt8173.c
+++ b/drivers/clk/mediatek/clk-mt8173.c
@@ -12,6 +12,7 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/clk.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/slab.h>