Bump buidlroot version to 2018.02.6

bsp/buildroot/board/zynq/genimage.cfg

@@ -0,0 +1,25 @@
+image boot.vfat {
+	vfat {
+		files = {
+			"boot.bin",
+			"u-boot.img",
+			"devicetree.dtb",
+			"uImage"
+		}
+		file uramdisk.image.gz {
+			image = "rootfs.cpio.uboot"
+		}
+	}
+	size = 32M
+}
+
+image sdcard.img {
+	hdimage {
+	}
+
+	partition boot {
+		partition-type = 0xC
+		bootable = "true"
+		image = "boot.vfat"
+	}
+}