printk: Move locking annotation to printk.c

With Sparse support gone, Clang is a bit more strict and warns:

./include/linux/console.h:492:50: error: use of undeclared identifier 'console_mutex'
  492 | extern void console_list_unlock(void) __releases(console_mutex);

Since it does not make sense to make console_mutex itself global, move
the annotation to printk.c. Context analysis remains disabled for
printk.c.

This is needed to enable context analysis for modules that include
<linux/console.h>.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-34-elver@google.com

kernel/printk/printk.c

@@ -245,6 +245,7 @@ int devkmsg_sysctl_set_loglvl(const struct ctl_table *table, int write,
  * For console list or console->flags updates
  */
 void console_list_lock(void)
+	__acquires(&console_mutex)
 {
 	/*
 	 * In unregister_console() and console_force_preferred_locked(),
@@ -269,6 +270,7 @@ EXPORT_SYMBOL(console_list_lock);
  * Counterpart to console_list_lock()
  */
 void console_list_unlock(void)
+	__releases(&console_mutex)
 {
 	mutex_unlock(&console_mutex);
 }