ar71xx: add model detection for the MERCURY MW4530R board

Mercury MW4530R is a TP-Link TL-WDR4310 clone but
with a much lower price tag (~ $40). This patch
is tested to work at trunk r37525.

Signed-off-by: Leon Xu <ylxu72@gmail.com>
Patchwork: http://patchwork.openwrt.org/patch/3856/
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

SVN-Revision: 37570

target/linux/ar71xx/base-files/lib/ar71xx.sh

@@ -162,6 +162,9 @@ tplink_board_detect() {
 	"431000"*)
 		model="TP-Link TL-WDR4310"
 		;;
+	"453000"*)
+		model="MERCURY MW4530R"
+		;;
 	*)
 		hwver=""
 		;;