qemu: Use ULL instead of uint64_t for RDMA GID event

In the previous commit we are using uint64_t for storing subnet
prefix and interface id that qemu reports in
RDMA_GID_STATUS_CHANGED event. We also report them in some debug
messages. This poses a problem because uint64_t can be UL or ULL
depending on the host architecture and hence we wouldn't know
which format to use. Switch to ULL which is big enough and
doesn't suffer from the issue.

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