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>