audit: mark audit_log_vformat() with __printf() attribute

audit_log_vformat() is using printf() type of format, and GCC compiler
(Debian 14.2.0-17) is not happy about this:

kernel/audit.c:1978:9: error: function ‘audit_log_vformat’
  might be a candidate for ‘gnu_printf’ format attribute
kernel/audit.c:1987:17: error: function ‘audit_log_vformat’
  might be a candidate for ‘gnu_printf’ format attribute

Fix the compilation errors (`make W=1` when CONFIG_WERROR=y, which is
default) by adding __printf() attribute.

Signed-off-by: Andy Shevchenko <[email protected]>
[PM: commit description line wrap fixes]
Signed-off-by: Paul Moore <[email protected]>

Author: andy-shev

kernel/audit.c

@@ -1956,8 +1956,8 @@ static inline int audit_expand(struct audit_buffer *ab, int extra)
  * will be called a second time.  Currently, we assume that a printk
  * can't format message larger than 1024 bytes, so we don't either.
  */
-static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
-			      va_list args)
+static __printf(2, 0)
+void audit_log_vformat(struct audit_buffer *ab, const char *fmt, va_list args)
 {
 	int len, avail;
 	struct sk_buff *skb;