Fix ISP_FC_LIP and ISP_RESCAN on big-endian 64-bit systems.

[brooks]

Summary

For _IO() ioctls, addr is a pointer to uap->data which is a caddr_t.
When the caddr_t stores an int, dereferencing addr as an (int *) results
in truncation on little-endian 64-bit systems and corruption (owing to
extracting top bits) on big-endian 64-bit systems. In practice the
value of chan was probably always zero on systems of the latter type.

[mav]

It makes some sense to me, but I suspect that this code is generally dead, since I don't know any user-space tool using it. Ken, do you?