platform/chrome: cros_ec_typec: Move mux flag checks

Move mux and role flag checks inside of cros_typec_configure_mux(),
which is a more logical location for them.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/chrome-platform/20220208184721.1697194-2-pmalani@chromium.org/