arm: dts: mt8135: Move pinfunc to include/dt-bindings/pinctrl

Move mt8135-pinfunc.h into include/dt-bindings/pinctrl so that we can
include it in yaml examples.
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Link: https://lore.kernel.org/r/20210804044033.3047296-1-hsinyi@chromium.orgSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/mt8135.dtsi

@@ -9,7 +9,7 @@
 #include <dt-bindings/interrupt-controller/irq.h>
 #include <dt-bindings/interrupt-controller/arm-gic.h>
 #include <dt-bindings/reset/mt8135-resets.h>
-#include "mt8135-pinfunc.h"
+#include <dt-bindings/pinctrl/mt8135-pinfunc.h>
 
 / {
 	#address-cells = <2>;