microblaze: pci-common cleanup

Use set_dma_ops and remove now used-once oddly named temp pointer sd.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>