arm: spear: Enable THUMB mode on x600 board

To reduce the size of the U-Boot image on the x600 board, lets enable
the THUMB mode. This reduces the overall size to less than 0x6000
bytes. Fitting it again in the onboard NOR flash.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>

include/configs/x600.h

@@ -17,6 +17,7 @@
 #define CONFIG_SPEAR600				/* SPEAr600 SoC */
 #define CONFIG_X600				/* on X600 board */
 #define CONFIG_SYS_GENERIC_BOARD
+#define CONFIG_SYS_THUMB_BUILD
 
 #include <asm/arch/hardware.h>