Bump buildroot to 2019.02

bsp/buildroot/board/bananapi/bananapi-m2-ultra/genimage.cfg

@@ -0,0 +1,33 @@
+image boot.vfat {
+	vfat {
+		files = {
+			"zImage",
+			"sun8i-r40-bananapi-m2-ultra.dtb",
+			"boot.scr"
+		}
+	}
+	size = 64M
+}
+
+image sdcard.img {
+	hdimage {
+	}
+
+	partition u-boot {
+		in-partition-table = "no"
+		image = "u-boot-sunxi-with-spl.bin"
+		offset = 8192
+		size = 1040384 # 1MB - 8192
+	}
+
+	partition boot {
+		partition-type = 0xC
+		bootable = "true"
+		image = "boot.vfat"
+	}
+
+	partition rootfs {
+		partition-type = 0x83
+		image = "rootfs.ext4"
+	}
+}