loop: Remove struct loop_func_table

The struct is introduced in the commit 754d967
("loop: remove loop.h"), but it is not used now.
So remove it.

No functional changes.

Signed-off-by: Zhu Yanjun <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: zhuyj

drivers/block/loop.c

@@ -45,8 +45,6 @@ enum {
 	Lo_deleting,
 };
 
-struct loop_func_table;
-
 struct loop_device {
 	int		lo_number;
 	loff_t		lo_offset;