mx6_common: remove dead code

There is an #ifdef and #endif with nothing in between.  This patch simply
removes this dead/useless code.

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>

include/configs/mx6_common.h

@@ -65,9 +65,6 @@
 #define CONFIG_SYS_CBSIZE	512
 #define CONFIG_SYS_MAXARGS	32
 
-#ifndef CONFIG_SYS_DCACHE_OFF
-#endif
-
 /* GPIO */
 #define CONFIG_MXC_GPIO