audit: audit_string_contains_control can be boolean

This patch makes audit_string_contains_control return bool to improve
readability due to this particular function only using either one or
zero as its return value.

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
[PM: tweaked subject line]
Signed-off-by: Paul Moore <pmoore@redhat.com>
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 69844b6..20eba1e 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -457,7 +457,7 @@
 extern __printf(2, 3)
 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...);
 extern void		    audit_log_end(struct audit_buffer *ab);
-extern int		    audit_string_contains_control(const char *string,
+extern bool		    audit_string_contains_control(const char *string,
 							  size_t len);
 extern void		    audit_log_n_hex(struct audit_buffer *ab,
 					  const unsigned char *buf,