clk: qcom: clk-rcg2: Update logic to calculate D value for RCG

The display pixel clock has a requirement on certain newer platforms to
support M/N as (2/3) and the final D value calculated results in
underflow errors.
As the current implementation does not check for D value is within
the accepted range for a given M & N value. Update the logic to
calculate the final D value based on the range.

Fixes: 99cbd064 ("clk: qcom: Support display RCG clocks")
Signed-off-by: Taniya Das <tdas@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220227175536.3131-1-tdas@codeaurora.org