bitwise-AND-ing instead of bitwise-OR-ing in make_cuda_host_alloc_flags

[eyalroz]

in cuda::memory::detail_ we have:

inline unsigned make_cuda_host_alloc_flags(allocation_options options)

combines to bits into a mask. But - currently, instead of combining them with bitwise-or, it used bitwise-and, which is wrong and always produces 0.