dt-bindings: clock: Move at91.h to dt-bindigs/clock

Most of the clock related dt-binding header files are located in
dt-bindings/clock folder. It would be good to keep all the similar
header files at a single location.

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
CC: Rob Landley <rob@landley.net>
CC: Andrew Victor <linux@maxim.org.za>
CC: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Acked-by: Boris BREZILLON <b.brezillon.dev@gmail.com>
[nicolas.ferre@atmel.com: add new at91sam9261 & at91sam9rl]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/boot/dts/at91sam9rl.dtsi

@@ -8,7 +8,7 @@
 
 #include "skeleton.dtsi"
 #include <dt-bindings/pinctrl/at91.h>
-#include <dt-bindings/clk/at91.h>
+#include <dt-bindings/clock/at91.h>
 #include <dt-bindings/interrupt-controller/irq.h>
 #include <dt-bindings/gpio/gpio.h>