io: Fix printing 4 bytes memory on 64 bit systems

On 64 bit Linux systems long is 8 bytes long, on 32 bit Linux systems it
is 4 bytes long. Here we want to print 4 bytes and not 8 bytes, use int
instead of long.

This fixes printing 4 bytes on 64 bit systems.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>