x86, ptrace: add bts_struct size to status command

Return the size of bts_struct in the PTRACE_BTS_STATUS command.
Change types to u32.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/ptrace.c

@@ -787,6 +787,8 @@ static int ptrace_bts_status(struct task_struct *child,
 			cfg.flags |= PTRACE_BTS_O_SCHED;
 	}
 
+	cfg.bts_size = sizeof(struct bts_struct);
+
 	if (copy_to_user(ucfg, &cfg, sizeof(cfg)))
 		return -EFAULT;