ARM: Add X600 board support (SPEAr600 based)

This patch adds support for the X600 SPEAr600 based board. Its also
the first SPEAr600 board that uses the newly introduced SPEAr600
SPL support. Xloader is not necessary any more. By using the new
"u-boot.spr" make target, one image will generated containing both,
U-Boot SPL (with mkimage header as needed by the SPEAr BootROM, and
the main U-Boot with mkimage header.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Amit Virdi <amit.virdi@st.com>
Cc: Vipin Kumar <vipin.kumar@st.com>
diff --git a/boards.cfg b/boards.cfg
index f9df74b..5eb35c9 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -218,6 +218,7 @@
 spear600_nand                arm         arm926ejs   spear600            spear          spear       spear6xx_evb:spear600,nand
 spear600_usbtty              arm         arm926ejs   spear600            spear          spear       spear6xx_evb:spear600,usbtty
 spear600_usbtty_nand         arm         arm926ejs   spear600            spear          spear       spear6xx_evb:spear600,usbtty,nand
+x600			     arm         arm926ejs   -                   spear          spear       x600
 versatileab                  arm         arm926ejs   versatile           armltd         versatile   versatile:ARCH_VERSATILE_AB
 versatilepb                  arm         arm926ejs   versatile           armltd         versatile   versatile:ARCH_VERSATILE_PB
 versatileqemu                arm         arm926ejs   versatile           armltd         versatile   versatile:ARCH_VERSATILE_QEMU,ARCH_VERSATILE_PB