clk: qcom: gcc-msm8996: start getting rid of xo clk

The "xo" fixed_factor clock is a leftover/hack from a time when we
couldn't make rpmhcc the root of all clocks. It is going to be removed
once all users of this clock are converted to use clocks specified
through the DTS. Replace internal usage of the xo clock with the cxo
(RPM_SMD_BB_CLK1) parent, specifying xo_board as a fallback.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211228045415.20543-17-dmitry.baryshkov@linaro.org