virnuma: Allow multiple nodes for preferred policy

virnuma: Allow multiple nodes for preferred policy

In the past, the preferred policy
(VIR_DOMAIN_NUMATUNE_MEM_PREFERRED) required exactly one (host)
NUMA node. This made sense because:

  1) the libnuma API - numa_set_preferred() allowed exactly one
     node, because
  2) corresponding kernel syscall (__NR_set_mempolicy) accepted
     exactly one node (for MPOL_PREFERRED mode).

But things have changed since then. Firstly, kernel introduced
new MPOL_PREFERRED_MANY mode (v5.15-rc1~107^2~21) which was then
exposed in libnuma as numa_set_preferred_many() (v2.0.15~24).

Fortunately, libnuma also exposes numa_has_preferred_many() which
returns whether the kernel has support for the new mode (1) or
not (0).

Putting this all together, we can lift our check for sufficiently
new kernel and libnuma.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2151064
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>