mtd-utils: nanddump: fix writing big images on 32bit machines
When writing a full 4GiB NAND to a file end_addr becomes 0x100000000.
With that writing out the first page to the file doesn't happen
because size_left is calculated to 0x100000000 - 0 = 0x100000000
which is then truncated to 32bit and becomes zero. Fix this by
using an appropriate 64bit type for size_left.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>