block/rnbd: add support for REQ_OP_WRITE_ZEROES

Remove REQ_OP_WRITE_SAME in favour of REQ_OP_WRITE_ZEROES.

Signed-off-by: Santosh Pradhan <santosh.pradhan@ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Grzegorz Prajsner <grzegorz.prajsner@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Link: https://lore.kernel.org/r/20231124213422.113449-2-haris.iqbal@ionos.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>