i2c: hisi: Add initial device tree support

The HiSilicon I2C controller can be used on embedded platform, which
boot from devicetree.

Signed-off-by: Weilong Chen <chenweilong@huawei.com>
Acked-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>