clk: qcom: gcc-msm8939: use ARRAY_SIZE instead of specifying num_parents

Use ARRAY_SIZE() instead of manually specifying num_parents. This makes
adding/removing entries to/from parent_data easy and errorproof.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220928145609.375860-4-dmitry.baryshkov@linaro.org