dt-bindings: arm: qcom: Add Xiaomi Poco F1 EBBG variant bindings

Add documentation for "xiaomi,beryllium-ebbg" device.

Signed-off-by: Joel Selvaraj <joelselvaraj.oss@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220909035447.36674-3-joelselvaraj.oss@gmail.com