fsdax: mark the iomap argument to dax_iomap_sector as const

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

fs/dax.c

@@ -1005,7 +1005,7 @@ int dax_writeback_mapping_range(struct address_space *mapping,
 }
 EXPORT_SYMBOL_GPL(dax_writeback_mapping_range);
 
-static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos)
+static sector_t dax_iomap_sector(const struct iomap *iomap, loff_t pos)
 {
 	return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9;
 }