x86/cpuidle: don't count C1 multiple times

Commit 4ca6f9f0 ("x86/cpuidle: publish new states only after fully
initializing them") resulted in the state counter to be incremented
for C1 despite that using a fixed table entry (and the statically
initialized counter value already accounting for it and C0).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -1015,7 +1015,7 @@ static void set_cx(
     cx->target_residency = cx->latency * latency_factor;
 
     smp_wmb();
-    acpi_power->count++;
+    acpi_power->count += (cx->type != ACPI_STATE_C1);
     if ( cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 )
         acpi_power->safe_state = cx;
 }