board/ti/omap730p2/flash.c: Fix GCC 4.6 build warnings

Fix:
flash.c: In function 'flash_get_offsets':
flash.c:122:10: warning: variable 'pOrgDef' set but not used
[-Wunused-but-set-variable]
flash.c: In function 'flash_erase':
flash.c:263:6: warning: variable 'flag' set but not used
[-Wunused-but-set-variable]
flash.c: In function 'write_data':
flash.c:439:6: warning: variable 'flag' set but not used
[-Wunused-but-set-variable]

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Dave Peverley <dpeverley@mpc-data.co.uk>
Acked-by: Tom Rini <trini@ti.com>