ublk: don't suggest CONFIG_BLK_DEV_UBLK=Y

The CONFIG_BLK_DEV_UBLK help text suggests setting the config option to
Y so task_work_add() can be used to dispatch I/O, improving performance.
However, this mechanism was removed in commit 29dc5d0 ("ublk: kill
queuing request by task_work_add"). So remove this paragraph from the
config help text.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Uday Shankar <ushankar@purestorage.com>
Link: https://lore.kernel.org/r/20250416004111.3242817-1-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/Kconfig

@@ -388,12 +388,6 @@ config BLK_DEV_UBLK
 	  definition isn't finalized yet, and might change according to future
 	  requirement, so mark is as experimental now.
 
-	  Say Y if you want to get better performance because task_work_add()
-	  can be used in IO path for replacing io_uring cmd, which will become
-	  shared between IO tasks and ubq daemon, meantime task_work_add() can
-	  can handle batch more effectively, but task_work_add() isn't exported
-	  for module, so ublk has to be built to kernel.
-
 config BLKDEV_UBLK_LEGACY_OPCODES
 	bool "Support legacy command opcode"
 	depends on BLK_DEV_UBLK