clk: qcom: gcc-qcs404: sort out the cxo clock

The GCC driver registers the cxo clock as a thin wrapper around board's
xo_board clock. Nowadays we can use the xo_board directly in all the
clocks that use it. Use the fw_name "cxo" for this clock.

Reviewed-by: Konrad Dybcio <konrad.dybcio@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/20221226042154.2666748-12-dmitry.baryshkov@linaro.org