imx: imx8ulp: add ND/LD clock

imx: imx8ulp: add ND/LD clock

Add a new ddr script, defconfig for ND
Configure the clock for ND mode
changing A35 to 960MHz for OD mode
Update NIC CLK for the various modes
Introduce clock_init_early/late, late is used after pmic voltage
setting, early is used in the very early stage for upower mu, lpuart and
etc.

Note: NIC runs at 324MHz, 442MHz has some random kernel hang issue with
cpuidle enabled now.

Reviewed-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>