kgdb: add missing __percpu markup in arch/x86/kernel/kgdb.c

breakinfo->pev is a pointer to percpu pointer but was missing __percpu markup.
Add it.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

arch/x86/kernel/kgdb.c

@@ -194,7 +194,7 @@ static struct hw_breakpoint {
 	unsigned long		addr;
 	int			len;
 	int			type;
-	struct perf_event	**pev;
+	struct perf_event	* __percpu *pev;
 } breakinfo[HBP_NUM];
 
 static unsigned long early_dr7;