clk: imx: support fracn gppll

clk: imx: support fracn gppll

This PLL module is a Fractional-N synthesizer,
supporting 30-bit numerator and denominator. Numerator is a signed
number. It has feature to adjust fractional portion of feedback
divider dynamically. This fracn gppll is used in i.MX93.

Reviewed-by: Abel Vesa <abel.vesa@nxp.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20220228020908.2810346-5-peng.fan@oss.nxp.com
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>