dt-bindings: qcom: Document msm8916-thwc-uf896 and ufi001c

Document the new thwc,uf896/ufi001c device tree bindings used in their device
trees.

Signed-off-by: Yang Xiwen <forbidden405@foxmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>