ar71xx: remove obsolete '< KERNEL_VERSION(3, 15, 0)' checks

Because the oldest supported kernel version on the ar71xx target is 4.4,
the condition that the kernel version is smaller than 3.15.0 is always
false. Remove the obsolete checks from the target specific source files
to clean up the code a bit.

Signed-off-by: Gabor Juhos <juhosg@freemail.hu>

target/linux/ar71xx/files/arch/mips/ath79/dev-dsa.c

@@ -10,7 +10,6 @@
  */
 
 #include <linux/init.h>
-#include <linux/version.h>
 #include <linux/platform_device.h>
 
 #include <asm/mach-ath79/ath79.h>
@@ -30,11 +29,7 @@ void __init ath79_register_dsa(struct device *netdev,
 
 	d->netdev = netdev;
 	for (i = 0; i < d->nr_chips; i++)
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,15,0)
-		d->chip[i].mii_bus = miidev;
-#else
 		d->chip[i].host_dev = miidev;
-#endif
 
 	ar71xx_dsa_switch_device.dev.platform_data = d;
 	platform_device_register(&ar71xx_dsa_switch_device);

target/linux/ar71xx/files/drivers/gpio/gpio-nxp-74hc153.c

@@ -203,19 +203,7 @@ static int nxp_74hc153_remove(struct platform_device *pdev)
 	struct nxp_74hc153_platform_data *pdata = pdev->dev.platform_data;
 
 	if (nxp) {
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,15,0)
-		int err;
-
-		err = gpiochip_remove(&nxp->gpio_chip);
-		if (err) {
-			dev_err(&pdev->dev,
-				"unable to remove gpio chip, err=%d\n",
-				err);
-			return err;
-		}
-#else
 		gpiochip_remove(&nxp->gpio_chip);
-#endif
 		gpio_free(pdata->gpio_pin_2y);
 		gpio_free(pdata->gpio_pin_1y);
 		gpio_free(pdata->gpio_pin_s1);