ANDROID: cpu/hotplug: create vendor hook for cpu_up/cpu_down

Include a vendor hook for cpu_up and cpu_down to force the
rebuilding of scheduling domains prior to issuing a new
cpu up/down.  Include a Kernel Export for
cpuset_wait_for_hotplug such that vendor hooks may refer
to this functionality, to ensure scheduling domains are
complete.

Bug: 176152285
Change-Id: I778dbc5e4f9d613f39b8c61f244c0f33020a3dd3
Signed-off-by: Stephen Dickey <dickey@codeaurora.org>

kernel/cpu.c

@@ -41,6 +41,7 @@
 
 #undef CREATE_TRACE_POINTS
 #include <trace/hooks/sched.h>
+#include <trace/hooks/cpu.h>
 
 #include "smpboot.h"
 
@@ -1070,6 +1071,8 @@ static int cpu_down(unsigned int cpu, enum cpuhp_state target)
 {
 	int err;
 
+	trace_android_vh_cpu_down(NULL);
+
 	cpu_maps_update_begin();
 	err = cpu_down_maps_locked(cpu, target);
 	cpu_maps_update_done();
@@ -1499,6 +1502,8 @@ static int cpu_up(unsigned int cpu, enum cpuhp_state target)
 		return -EINVAL;
 	}
 
+	trace_android_vh_cpu_up(NULL);
+
 	/*
 	 * CPU hotplug operations consists of many steps and each step
 	 * calls a callback of core kernel subsystem. CPU hotplug-in