clk: imx: Update the pllv4 to support imx8ulp

The PLLs used on i.MX8ULP is mostly the same as on i.MX7ULP,
except the PLL register offset is changed. Change the PLLv4
driver for code reuse on i.MX7ULP and i.MX8ULP.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@nxp.com>
Link: https://lore.kernel.org/r/20210914065208.3582128-3-ping.bai@nxp.com


Signed-off-by: Abel Vesa <abel.vesa@nxp.com>