clk: imx: imx8ulp: Add divider closest support to get more accurate clock rate

If a divider's parent clock has fractional part, it will hard to round out a
more accurate clock rate for this divider, add the 'CLK_DIVIDER_ROUND_CLOSEST' flags
for such divider to get a more accurate clock rate.

Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20230331063814.2462059-3-peng.fan@oss.nxp.com


Signed-off-by: Abel Vesa <abel.vesa@linaro.org>