ramips: add support for Airlink101 AR670W

This is a RT2880-based board, 32MB RAM, 4MB flash. The bootloader
is a hacked u-Boot that reads an LZMA image directly, so we skip
generating the uImage header and enable the lzma mtdsplit parser.

Signed-off-by: Claudio Leite <leitec@staticky.com>

SVN-Revision: 43153

target/linux/ramips/base-files/lib/upgrade/platform.sh

@@ -110,6 +110,13 @@ platform_check_image() {
 		}
 		return 0
 		;;
+	ar670w)
+		[ "$magic" != "6d000080" ] && {
+			echo "Invalid image type."
+			return 1
+		}
+		return 0
+		;;
 	cy-swr1100 |\
 	dir-610-a1 |\
 	dir-645)