qemu: Always check nodeset provided to numatune

qemu: Always check nodeset provided to numatune

Up until commit 629282d88454, using mode=restrictive caused
virNumaSetupMemoryPolicy() to be called from qemuProcessHook(),
and that in turn resulted in virNumaNodesetIsAvailable() being
called and the nodeset being validated.

After that change, the only validation for the nodeset is the one
happening in qemuBuildMemoryBackendProps(), which is skipped when
using mode=restrictive.

Make sure virNumaNodesetIsAvailable() is called whenever a
nodeset has been provided by the user, regardless of the mode.

https://bugzilla.redhat.com/show_bug.cgi?id=2156289

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>