clk: qcom: mmcc-sdm660: Use ARRAY_SIZE for num_parents

Where possible, use ARRAY_SIZE to determine the number of parents in
clk_parent_data, instead of hardcoding it.
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Link: https://lore.kernel.org/r/20210829204822.289829-4-marijn.suijten@somainline.orgSigned-off-by: Stephen Boyd <sboyd@kernel.org>