fs: Remove CONFIG_SRCU

Now that the SRCU Kconfig option is unconditionally selected, there is
no longer any point in conditional compilation based on CONFIG_SRCU.
Therefore, remove the #ifdef and throw away the #else clause.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <linux-fsdevel@vger.kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: John Ogness <john.ogness@linutronix.de>

fs/locks.c

@@ -1889,7 +1889,6 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
 }
 EXPORT_SYMBOL(generic_setlease);
 
-#if IS_ENABLED(CONFIG_SRCU)
 /*
  * Kernel subsystems can register to be notified on any attempt to set
  * a new lease with the lease_notifier_chain. This is used by (e.g.) nfsd
@@ -1923,30 +1922,6 @@ void lease_unregister_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(lease_unregister_notifier);
 
-#else /* !IS_ENABLED(CONFIG_SRCU) */
-static inline void
-lease_notifier_chain_init(void)
-{
-}
-
-static inline void
-setlease_notifier(long arg, struct file_lock *lease)
-{
-}
-
-int lease_register_notifier(struct notifier_block *nb)
-{
-	return 0;
-}
-EXPORT_SYMBOL_GPL(lease_register_notifier);
-
-void lease_unregister_notifier(struct notifier_block *nb)
-{
-}
-EXPORT_SYMBOL_GPL(lease_unregister_notifier);
-
-#endif /* IS_ENABLED(CONFIG_SRCU) */
-
 /**
  * vfs_setlease        -       sets a lease on an open file
  * @filp:	file pointer