arm: mxs: Correct CONFIG_SPL_NO_CPU_SUPPORT option

At present this is defined in Kconfig but there is a separate one in the
CONFIG whitelist. It looks like these are duplicates.

Rename the non-Kconfig one and remove it from the whitelist.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/configs/mxs.h b/include/configs/mxs.h
index 6cadd72..e079f80 100644
--- a/include/configs/mxs.h
+++ b/include/configs/mxs.h
@@ -45,7 +45,7 @@
 
 /* SPL */
 #ifndef CONFIG_SPL_FRAMEWORK
-#define CONFIG_SPL_NO_CPU_SUPPORT_CODE
+#define CONFIG_SPL_NO_CPU_SUPPORT
 #define CONFIG_SPL_START_S_PATH	"arch/arm/cpu/arm926ejs/mxs"
 #endif