Convert the clock driver to specify parent data rather than parent
names, to actually bind using 'clock-names' specified in the DTS rather
than global clock names. Use parent_hws where possible to refer parent
clocks directly, skipping the lookup.

Note, the system names for xo clocks were changed from "cxo" to
"cxo_board" to follow the example of other platforms. This switches the
clocks to use DT-provided "cxo_board" clock instead of manually
registered "cxo" clock and allows us to drop the cxo clock.
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230512211727.3445575-8-dmitry.baryshkov@linaro.orgSigned-off-by: Bjorn Andersson <andersson@kernel.org>