rk3288: add iomux operation

BUG=chrome-os-partner:29778
TEST=Build coreboot

Change-Id: Ia19f8084a945992d9f252eb080c6c5c9990ac7de
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 30d02610e8e1e018025c2c1c970fb5b33d67d51b
Original-Change-Id: I8f273f8850e4792ca976bb7c2ed39cbe501401f2
Original-Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Original-Signed-off-by: huang lin <hl@rock-chips.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/209461
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Original-Commit-Queue: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/8861
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)
2 files changed