Since ib_dma_map_single can fail use ib_dma_mapping_error to check
for errors.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Acked-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NDoug Ledford <dledford@redhat.com>