fs/squashfs: use lldiv function for math

When compling for x86:
u-boot/fs/squashfs/sqfs.c:90: undefined reference to `__udivmoddi4'

Signed-off-by: Kasper Revsbech <kasper.revsbech.ext@siemensgamesa.com>
Tested-by: Sean Nyekjaer <sean@geanix.com>