board/cogent/flash.c: Fix GCC 4.6 buiild warning

Fix:
flash.c: In function 'flash_init':
flash.c:295:16: warning: variable 'fip' set but not used
[-Wunused-but-set-variable]

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Murray Jensen <Murray.Jensen@csiro.au>
diff --git a/board/cogent/flash.c b/board/cogent/flash.c
index e6c85b6..ec3f94d 100644
--- a/board/cogent/flash.c
+++ b/board/cogent/flash.c
@@ -23,6 +23,7 @@
 
 #include <common.h>
 #include <board/cogent/flash.h>
+#include <linux/compiler.h>
 
 flash_info_t	flash_info[CONFIG_SYS_MAX_FLASH_BANKS]; /* info for FLASH chips	*/
 
@@ -292,7 +293,7 @@
 {
 	unsigned long total;
 	int i;
-	flash_info_t *fip;
+	__maybe_unused flash_info_t *fip;
 
 	/* Init: no FLASHes known */
 	for (i=0; i<CONFIG_SYS_MAX_FLASH_BANKS; ++i) {