zynq_fpga: use sgtable-based scatterlist wrappers

Use common wrappers operating directly on the struct sg_table objects to
fix incorrect use of statterlists related calls. dma_unmap_sg() function
has to be called with the number of elements originally passed to the
dma_map_sg() function, not the one returned in sgtable's nents.

CC: stable@vger.kernel.org
Fixes: 425902f5 ("fpga zynq: Use the scatterlist interface")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20250616120932.1090614-1-m.szyprowski@samsung.com


Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>