The last_block argument to nand_erase() is checked against nand->num_blocks,
but the highest valid block number is (total - 1), the test for invalid should
be ">=" rather than ">".
Signed-off-by: Jon Povey <jon.povey@racelogic.co.uk>
Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>