Fix:
flash.c: In function 'flash_erase_1':
flash.c:514:24: warning: variable 'l_sect' set but not used
[-Wunused-but-set-variable]
flash.c: In function 'flash_erase_2':
flash.c:956:24: warning: variable 'l_sect' set but not used
[-Wunused-but-set-variable]

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Stefan Roese <sr@denx.de>
Acked-by: Stefan Roese <sr@denx.de>