fix servo_v2/v3 usbpd_uart_routing errors

There is no usbpd_uart_routing control for servo v2 or v3. Add a control
mapping the control to the na driver.

BUG=b:71556454
BRANCH=none
TEST=Start servo on fizz using servo v2 and v4. Make sure there a no
errors and the cr50 console works.

Change-Id: Ief0d2ed7fb6498c4ea916fbbd8ab1eb4cf0bba8c
Signed-off-by: Mary Ruthven <mruthven@google.com>
Reviewed-on: https://chromium-review.googlesource.com/994692
Commit-Ready: Mary Ruthven <mruthven@chromium.org>
Tested-by: Mary Ruthven <mruthven@chromium.org>
Reviewed-by: Wai-Hong Tam <waihong@google.com>
2 files changed