virbpf: Fix typecast to __aligned_u64 type

virbpf: Fix typecast to __aligned_u64 type

In functions implemented here we fill this attr union (type of
bpf_attr) and just pass it to syscall(2). Thing is that some of
the union members are type of __aligned_u64. This is not regular
uint64_t. This one is explicitly aligned to 8 bytes, while
uint64_t can be aligned to 4 bytes (on 32 bits). We've used
explicit typecast to uint64_t to shut compiler which would
otherwise complain of assigning a pointer into an integer. Well,
we have uintptr_t just for that.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>