cpu/hotplug: Make HOTPLUG_PARALLEL independent of HOTPLUG_SMT

Provide stub functions for SMT related parallel bring up functions so that
HOTPLUG_PARALLEL can work without HOTPLUG_SMT.

Signed-off-by: Jiaxun Yang <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/all/[email protected]

Author: FlyGoat

kernel/cpu.c

@@ -1808,6 +1808,7 @@ static int __init parallel_bringup_parse_param(char *arg)
 }
 early_param("cpuhp.parallel", parallel_bringup_parse_param);
 
+#ifdef CONFIG_HOTPLUG_SMT
 static inline bool cpuhp_smt_aware(void)
 {
 	return cpu_smt_max_threads > 1;
@@ -1817,6 +1818,16 @@ static inline const struct cpumask *cpuhp_get_primary_thread_mask(void)
 {
 	return cpu_primary_thread_mask;
 }
+#else
+static inline bool cpuhp_smt_aware(void)
+{
+	return false;
+}
+static inline const struct cpumask *cpuhp_get_primary_thread_mask(void)
+{
+	return cpu_none_mask;
+}
+#endif
 
 /*
  * On architectures which have enabled parallel bringup this invokes all BP