printk: Add notation to console_srcu locking

printk: Add notation to console_srcu locking

kernel/printk/printk.c:284:5: sparse: sparse: context imbalance in
'console_srcu_read_lock' - wrong count at exit
include/linux/srcu.h:301:9: sparse: sparse: context imbalance in
'console_srcu_read_unlock' - unexpected unlock

Fixes: 6c4afa79147e ("printk: Prepare for SRCU console list protection")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20240820063001.36405-2-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>