Bus mastering is enabled by firmware, but when this driver
is unbinded bus mastering gets disabled by the PCI subsystem
which results interrupts not working when driver is reloaded.
Hence set bus mastering everytime in probe().

Also
- Converted pci_set_dma_mask() and pci_set_consistent_dma_mask()
  to dma_set_mask_and_coherent().
- Cleared transaction pending bit which gets set during
  driver unbind due to clearing of bus mastering (ME bit).
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>