fscrypt: remove unused 'mode' member of fscrypt_ctx

Nothing reads or writes fscrypt_ctx.mode, and it doesn't belong there
because a fscrypt_ctx is not tied to a specific encryption mode.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

include/linux/fscrypto.h

@@ -35,7 +35,6 @@ struct fscrypt_ctx {
 		struct list_head free_list;	/* Free list */
 	};
 	u8 flags;				/* Flags */
-	u8 mode;				/* Encryption mode for tfm */
 };
 
 /**