selftests: ublk: kublk: use ioctl-encoded opcodes

There are a couple of places in the kublk selftests ublk server which
use the legacy ublk opcodes. These operations fail (with -EOPNOTSUPP) on
a kernel compiled without CONFIG_BLKDEV_UBLK_LEGACY_OPCODES set. We
could easily require it to be set as a prerequisite for these selftests,
but since new applications should not be using the legacy opcodes, use
the ioctl-encoded opcodes everywhere in kublk.

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250401-ublk_selftests-v1-1-98129c9bc8bb@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: ps-ushankar

tools/testing/selftests/ublk/kublk.c

@@ -99,7 +99,7 @@ static int __ublk_ctrl_cmd(struct ublk_dev *dev,
 static int ublk_ctrl_stop_dev(struct ublk_dev *dev)
 {
 	struct ublk_ctrl_cmd_data data = {
-		.cmd_op	= UBLK_CMD_STOP_DEV,
+		.cmd_op	= UBLK_U_CMD_STOP_DEV,
 	};
 
 	return __ublk_ctrl_cmd(dev, &data);
@@ -169,7 +169,7 @@ static int ublk_ctrl_get_params(struct ublk_dev *dev,
 		struct ublk_params *params)
 {
 	struct ublk_ctrl_cmd_data data = {
-		.cmd_op	= UBLK_CMD_GET_PARAMS,
+		.cmd_op	= UBLK_U_CMD_GET_PARAMS,
 		.flags	= CTRL_CMD_HAS_BUF,
 		.addr = (__u64)params,
 		.len = sizeof(*params),