jbd2: remove unused t_handle_lock

Since commit f7f497cb ("jbd2: kill t_handle_lock
transaction spinlock"), this lock has been no use.

Fixes: f7f497cb ("jbd2: kill t_handle_lock transaction spinlock")
Signed-off-by: Wang Jianjian <wangjianjian0@foxmail.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/tencent_8477CBE568348A1862C64E393D587B342008@qq.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

include/linux/jbd2.h

@@ -630,11 +630,6 @@ struct transaction_s
 	 */
 	struct list_head	t_inode_list;
 
-	/*
-	 * Protects info related to handles
-	 */
-	spinlock_t		t_handle_lock;
-
 	/*
 	 * Longest time some handle had to wait for running transaction
 	 */