ublk: fix command op code check

In case of CONFIG_BLKDEV_UBLK_LEGACY_OPCODES, type of cmd opcode could
be 0 or 'u'; and type can only be 'u' if CONFIG_BLKDEV_UBLK_LEGACY_OPCODES
isn't set.

So fix the wrong check.

Fixes: 2d786e6 ("block: ublk: switch to ioctl command encoding")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230505153142.1258336-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Ming Lei

drivers/block/ublk_drv.c

@@ -1281,7 +1281,7 @@ static inline int ublk_check_cmd_op(u32 cmd_op)
 {
 	u32 ioc_type = _IOC_TYPE(cmd_op);
 
-	if (IS_ENABLED(CONFIG_BLKDEV_UBLK_LEGACY_OPCODES) && ioc_type != 'u')
+	if (!IS_ENABLED(CONFIG_BLKDEV_UBLK_LEGACY_OPCODES) && ioc_type != 'u')
 		return -EOPNOTSUPP;
 
 	if (ioc_type != 'u' && ioc_type != 0)