x86/time: gtsc_to_gtime() is HVM-only

Omit the function when HVM=n. With that the !HVM logic can also go away;
leave an assertion.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>

xen/arch/x86/time.c

@@ -2837,14 +2837,13 @@ uint64_t gtime_to_gtsc(const struct domain *d, uint64_t time)
     return scale_delta(time, &d->arch.ns_to_vtsc);
 }
 
+#ifdef CONFIG_HVM
 uint64_t gtsc_to_gtime(const struct domain *d, uint64_t tsc)
 {
-    u64 time = scale_delta(tsc, &d->arch.vtsc_to_ns);
-
-    if ( !is_hvm_domain(d) )
-        time += d->arch.vtsc_offset;
-    return time;
+    ASSERT(is_hvm_domain(d));
+    return scale_delta(tsc, &d->arch.vtsc_to_ns);
 }
+#endif /* CONFIG_HVM */
 
 uint64_t pv_soft_rdtsc(const struct vcpu *v, const struct cpu_user_regs *regs)
 {