armv7: rename cache related CONFIG flags

Replace the cache related CONFIG flags with more meaningful
names. Following are the changes:

CONFIG_L2_OFF	     -> CONFIG_SYS_L2CACHE_OFF
CONFIG_SYS_NO_ICACHE -> CONFIG_SYS_ICACHE_OFF
CONFIG_SYS_NO_DCACHE -> CONFIG_SYS_DCACHE_OFF

Signed-off-by: Aneesh V <aneesh@ti.com>
V2:
 * Changed CONFIG_L2_OFF -> CONFIG_SYS_NO_L2CACHE
V4:
 * Changed all three flags to the final names suggested as above
   and accordingly changed the commit message

include/configs/xm250.h

diff --git a/include/configs/xm250.h b/include/configs/xm250.h
index d61c2a4..32544fed 100644
--- a/include/configs/xm250.h
+++ b/include/configs/xm250.h
@@ -38,7 +38,7 @@
 #define	CONFIG_SYS_TEXT_BASE	0x0
 
 /* we will never enable dcache, because we have to setup MMU first */
-#define CONFIG_SYS_NO_DCACHE
+#define CONFIG_SYS_DCACHE_OFF
 
 /*
  * Size of malloc() pool; this lives below the uppermost 128 KiB which are