srcu: Fix typo s/srcu_check_read_flavor()/__srcu_check_read_flavor()/

srcu: Fix typo s/srcu_check_read_flavor()/__srcu_check_read_flavor()/

This commit fixes a typo in which a comment needed to have been updated
from srcu_check_read_flavor() to __srcu_check_read_flavor().

Reported-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Closes: https://lore.kernel.org/all/b75d1fcd-6fcd-4619-bb5c-507fa599ee28@amd.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>