zbd: simplify zbd_open_zone()

zbd: simplify zbd_open_zone()

Similarly to zbd_close_zone(), directly pass a pointer to a zone
information structure to zbd_open_zone() instead of a zone number.

No functional changes.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>
Link: https://lore.kernel.org/r/20211214012413.464798-9-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>