i2c: rk3x: add i2c support for rk3399 soc

i2c: rk3x: add i2c support for rk3399 soc

- new method to caculate i2c timings for rk3399:
  There was an timing issue about "repeated start" time at the I2C
  controller of version0, controller appears to drop SDA at .875x (7/8)
  programmed clk high. On version 1 of the controller, the rule(.875x)
  isn't enough to meet tSU;STA
  requirements on 100k's Standard-mode. To resolve this issue,
  sda_update_config, start_setup_config and stop_setup_config for I2C
  timing information are added, new rules are designed to calculate
  the timing information at new v1.
- pclk and function clk are separated at rk3399.
- support i2c highspeed mode: 1.7MHz for rk3399

Change-Id: I413455cf94fe7486c40694059e2f0931433992bb
Signed-off-by: David Wu <david.wu@rock-chips.com>