rockchip: support i2c clock setting

BUG=None
TEST=Boot Veyron Pinky and measure i2c clock frequency

Original-Change-Id: I04d9fa75a05280885f083a828f78cf55811ca97d
Original-Signed-off-by: huang lin <hl@rock-chips.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/219660
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Commit-Queue: Julius Werner <jwerner@chromium.org>

Change-Id: Ie7ac3f2d0d76a4d3347bd469bf7af3295cc454fd
(cherry picked from commit 4b9b3c2f8b7c6cd189cb8f239508431ee08ebc52)
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9241
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)
7 files changed