spi: hisi-sfc-v3xx: factor out the bit definition of interrupt register

The definition of the register field in the interrupt corresponding
registers are the same. So factor them out to public place.

Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/1600950270-52536-4-git-send-email-yangyicong@hisilicon.com


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