clk: qcom: gcc-msm8994: Use ARRAY_SIZE() for num_parents

Don't rely on the programmer to enter the name of array elements, since the
computer can compute it with much less chance of making a mistake.
Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Link: https://lore.kernel.org/r/20210923162645.23257-9-konrad.dybcio@somainline.orgSigned-off-by: Stephen Boyd <sboyd@kernel.org>