clk: imx: clk-divider-gate: Switch to clk_divider.determine_rate

clk: imx: clk-divider-gate: Switch to clk_divider.determine_rate

.determine_rate is meant to replace .round_rate in CCF in the future.
Switch over to .determine_rate now that clk_divider_ops has gained
support for that.

Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Abel Vesa <abel.vesa@nxp.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Abel Vesa <abel.vesa@nxp.com>
Link: https://lore.kernel.org/r/20210702225145.2643303-3-martin.blumenstingl@googlemail.com
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>