spi: hisi-sfc-v3xx: add support for IRQ mode

The controller can work with interrupts, so add support for it.
Then we can work under IRQ mode or Poll mode now, if firmware
doesn't declare the IRQ support, it will fall back to Poll mode.

Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/1600950270-52536-5-git-send-email-yangyicong@hisilicon.com


Signed-off-by: Mark Brown <broonie@kernel.org>