Add support for Hikey960 board from HiSilicon based on their Kirin960 SoC. Peripherals supported: 1. GPIO 2. UART 3. I2C For GPIO only Chardev interface has been added since this board only supports >=4.15 kernel and using legacy sysfs interface is highly discouraged. Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Signed-off-by: malikabhi05 <abhishek.malik@intel.com>