arm64: dts: qcom: sdm845-lenovo-yoga-c630: Add Embedded Controller node

The Embedded Controller in the Lenovo Yoga C630 is accessible on &i2c1
and provides battery and adapter status, as well as altmode
notifications for the second USB Type-C port.

Add a definition for the EC and describe the two USB Type-C ports on the
laptop.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>