tools/cpuid: Plumb nested_virt down into xc_cpuid_apply_policy()

Nested Virt is the final special case in legacy CPUID handling.  Pass the
(poorly named) nested_hvm setting down into xc_cpuid_apply_policy() to break
the semantic dependency on HVM_PARAM_NESTEDHVM.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wl@xen.org>

tools/libs/ctrl/include/xenctrl.h

@@ -1826,7 +1826,7 @@ struct xc_xend_cpuid {
  * cases, and the generated policy must be compatible with a 4.13.
  *
  * Either pass a full new @featureset (and @nr_features), or adjust individual
- * features (@pae, @itsc).
+ * features (@pae, @itsc, @nested_virt).
  *
  * Then (optionally) apply legacy XEND overrides (@xend) to the result.
  */
@@ -1834,7 +1834,7 @@ int xc_cpuid_apply_policy(xc_interface *xch,
                           uint32_t domid, bool restore,
                           const uint32_t *featureset,
                           unsigned int nr_features, bool pae, bool itsc,
-                          const struct xc_xend_cpuid *xend);
+                          bool nested_virt, const struct xc_xend_cpuid *xend);
 int xc_mca_op(xc_interface *xch, struct xen_mc *mc);
 int xc_mca_op_inject_v2(xc_interface *xch, unsigned int flags,
                         xc_cpumap_t cpumap, unsigned int nr_cpus);