printk: add lock context annotation

acquire_console_semaphore_for_printk() releases logbuf_lock but
was missing proper annotation. Add it.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/printk.c

@@ -647,6 +647,7 @@ static inline int can_use_console(unsigned int cpu)
  * released but interrupts still disabled.
  */
 static int acquire_console_semaphore_for_printk(unsigned int cpu)
+	__releases(&logbuf_lock)
 {
 	int retval = 0;