dt-bindings: clock: qcom,gcc-apq8084: add GCC_MMSS_GPLL0_CLK_SRC

Add GCC_MMSS_GPLL0_CLK_SRC, the branch clock gating gpll0 clock for the
multimedia subsystem.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230111060402.1168726-3-dmitry.baryshkov@linaro.org