servo_v4: Add in missing controls used for USB detection/activation.

Added in the missing controls as aliases or new controls:
- usb_mux_oe1
- prtctl4_pwren
- usb_mux_sel1

BUG=chromium:599538
TEST=passed platform_ServoPowerStateController and could successfully
probe for correct usb device.

Change-Id: I4673145d7502ce03c159506b4bceb3cc88669b2c
Reviewed-on: https://chromium-review.googlesource.com/367953
Commit-Ready: Kevin Cheng <kevcheng@chromium.org>
Tested-by: Kevin Cheng <kevcheng@chromium.org>
Reviewed-by: Nick Sanders <nsanders@chromium.org>
Reviewed-by: Kevin Cheng <kevcheng@chromium.org>
1 file changed