servo: ccd_cr50: Reduce startup errors.

Cr50 supports a usbpd_uart_routing control, but it's really only
applicable for using servos with a flex.  When using CCD, there was no
driver defined for this control and it led to printing out some error
messages upon starting servod.  This commit fixes those issues as well
as re-adding the jtag_vref_sel controls even though they are no-ops for
CCD.

BUG=b:64461602
TEST=`sudo servod -b soraka` with a servo_v4 and verify that no
usbpd_uart_routing error is given.
TEST=Additonally, make sure that no errors are given regarding the
jtag_vref_sel controls either.

Change-Id: I1144540355852579e632e9b1d15ddf9a2fceb7fd
Signed-off-by: Aseda Aboagye <aaboagye@google.com>
Reviewed-on: https://chromium-review.googlesource.com/645775
Commit-Ready: Aseda Aboagye <aaboagye@chromium.org>
Tested-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Wai-Hong Tam <waihong@google.com>
1 file changed