CHROMIUM: config: enable USB_SERIAL_SIMPLE

Needed for accessing google serial ports.

Signed-off-by: Benson Leung <bleung@chromium.org>

BUG=chrome-os-partner:57511
TEST=See if Cr50s serial appear as /dev/ttyUSB[0-2]

Change-Id: I6cada4305085f409937b0295a2f5a181c2fc9821
Reviewed-on: https://chromium-review.googlesource.com/386808
Commit-Ready: Benson Leung <bleung@chromium.org>
Tested-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
1 file changed