null_blk: Print correct max open zones limit in null_init_zoned_dev()

commit 233e27b4 upstream.

When changing the maximum number of open zones, print that number
instead of the total number of zones.

Fixes: dc4d137e

 ("null_blk: add support for max open/active zone limit for zoned devices")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Link: https://lore.kernel.org/r/20240528062852.437599-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>