at91: create a legacy subtarget

In preparation for adding SAMA5D3 support, move the legacy ARMv5 based
platforms to a separate subtarget.

Signed-off-by: Florian Fainelli <florian@openwrt.org>

SVN-Revision: 42408

target/linux/at91/Makefile

@@ -11,7 +11,7 @@ BOARD:=at91
 MAINTAINER:=Claudio Mignanti <c.mignanti@gmail.com>
 BOARDNAME:=Atmel AT91
 FEATURES:=squashfs targz ext2 usb
-CPU_TYPE:=arm926ej-s
+SUBTARGETS:=legacy
 
 LINUX_VERSION:=3.10.49
 

target/linux/at91/legacy/target.mk

@@ -0,0 +1,7 @@
+BOARDNAME:=Legacy (ARMv5)
+CPU_TYPE:=arm926ej-s
+
+define Target/Description
+	Build generic firmware for legacy Atmel AT91 platforms
+	using the ARMv5 instruction set.
+endef