gpio-button-hotplug: fix data race

bh_event_add_var can be called by multiple threads concurrently,
so it shall not use a static char buffer

Signed-off-by: Andrey Erokhin <[email protected]>

package/kernel/gpio-button-hotplug/src/gpio-button-hotplug.c

@@ -107,7 +107,7 @@ static struct bh_map button_map[] = {
 static __printf(3, 4)
 int bh_event_add_var(struct bh_event *event, int argv, const char *format, ...)
 {
-	static char buf[128];
+	char buf[128];
 	char *s;
 	va_list args;
 	int len;