clk: imx: clk-composite-93: check slice busy

clk: imx: clk-composite-93: check slice busy

i.MX93 CCM ROOT STAT register has a SLICE_BUSY bit:
indication for clock generation logic is applying new setting.
0b - Clock generation logic is not busy.
1b - Clock generation logic is applying new setting.

So when set parent/rate/gate, need check this bit.

Introduce specific ops to do the work.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20220830033137.4149542-4-peng.fan@oss.nxp.com