ar71xx: fix build with kernel 4.4

The file linux/mdio-gpio.h was moved to linux/platform_data/mdio-gpio.h
in kernel 4.4

Reported-by: Arjen de Korte <arjen+openwrt@de-korte.org>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

SVN-Revision: 49193

target/linux/ar71xx/files/arch/mips/ath79/mach-om5pacv2.c

@@ -11,7 +11,11 @@
  */
 
 #include <linux/gpio.h>
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,4,0)
 #include <linux/mdio-gpio.h>
+#else
+#include <linux/platform_data/mdio-gpio.h> 
+#endif
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
 #include <linux/platform_device.h>

target/linux/ar71xx/files/arch/mips/ath79/mach-rb4xx.c

@@ -11,7 +11,11 @@
 
 #include <linux/platform_device.h>
 #include <linux/irq.h>
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,4,0)
 #include <linux/mdio-gpio.h>
+#else
+#include <linux/platform_data/mdio-gpio.h> 
+#endif
 #include <linux/mmc/host.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/flash.h>