ARM: socfpga: dts: convert to preprocessor includes

Convert all socfpga DT files to the dtc preprocessor include syntax.
This allows to include header files in the devicetrees like other
SoC-types already do.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Dinh Nguyen <dinguyen@altera.com>

arch/arm/boot/dts/socfpga_cyclone5.dtsi

@@ -16,7 +16,7 @@
  */
 
 /dts-v1/;
-/include/ "socfpga.dtsi"
+#include "socfpga.dtsi"
 
 / {
 	soc {