SPI: designware: pci: Switch over to MSI interrupts

Some devices support MSI interrupts. Let's at least try to use them in
platforms that provide MSI capability.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Link: https://lore.kernel.org/r/20191001081405.764161-1-felipe.balbi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>