The write_same and write_zeroes limits for SCSI are effectively the same,
so the current code works just fine.  But we plan to remove
REQ_OP_WRITE_SAME support, so switch to querying the write zeroes limit for
a zeroing WRITE SAME operation.

Link: https://lore.kernel.org/r/20220209082828.2629273-2-hch@lst.deReviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>