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>
diff --git a/arch/arm/mach-imx/imx8ulp/Kconfig b/arch/arm/mach-imx/imx8ulp/Kconfig
index d8b5ef7..bbdeaac 100644
--- a/arch/arm/mach-imx/imx8ulp/Kconfig
+++ b/arch/arm/mach-imx/imx8ulp/Kconfig
@@ -6,6 +6,12 @@
 config SYS_SOC
 	default "imx8ulp"
 
+config IMX8ULP_LD_MODE
+	bool
+
+config IMX8ULP_ND_MODE
+	bool "i.MX8ULP Low Driver Mode"
+
 choice
 	prompt "i.MX8ULP board select"
 	optional