rockchip: support pwm regulator

BUG=None
TEST=Boot Veyron Pinky and test the VDD_LOG

Original-Change-Id: Ie2eef918e04ba0e13879e915b0b0bef44aef550e
Original-Signed-off-by: huang lin <hl@rock-chips.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/219753
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Commit-Queue: Julius Werner <jwerner@chromium.org>

Change-Id: I444b47564d90b3480b351fdd8460e5b94e71927c
(cherry picked from commit 4491d9c4037161fd8c4cc40856167bf73182fda6)
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9240
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)
7 files changed