spi/pxa2xx-pci: Add support for Intel Braswell

Instead of one port we have 3 ports and all of them can take advantage of
the shared DMA controller.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>