ARM: dts: OMAP2+: Use pinctrl constants

Using constants for pinctrl allows a better readability, and removes
redundancy with comments.

Signed-off-by: Florian Vaussard <florian.vaussard@epfl.ch>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Benoit Cousson <benoit.cousson@linaro.org>

arch/arm/boot/dts/omap2.dtsi

@@ -9,6 +9,7 @@
  */
 
 #include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/pinctrl/omap.h>
 
 #include "skeleton.dtsi"