arm: imx: add i.MX8ULP EVK support
    
    Add i.MX8ULP EVK basic support, support SD/I2C/ENET/LPUART
    
    Log as below: I would keep some debug info for now, and after we move
    to be stable and production launch, we could drop that.
    
    U-Boot SPL 2021.07-rc4-00164-gb800e19a6b (Jun 29 2021 - 10:23:30 +0800)
    Normal Boot
    upower_init: soc_id=48
    upower_init: version:11.11.6
    upower_init: start uPower RAM service
    user_upwr_rdy_callb: soc=b
    user_upwr_rdy_callb: RAM version:12.6
    Turn on switches ok
    Turn on memories ok
    Clear DDR retention ok
    Poll for freq_chg_req on SIM register and change to F1 frequency.
    Poll for freq_chg_req on SIM register and change to F0 frequency.
    Poll for freq_chg_req on SIM register and change to F1 frequency.
    Poll for freq_chg_req on SIM register and change to F2 frequency.
    Poll for freq_chg_req on SIM register and change to F1 frequency.
    Poll for freq_chg_req on SIM register and change to F2 frequency.
    complete
    De-Skew PLL is locked and ready
    WDT:   Not found!
    Trying to boot from BOOTROM
    image offset 0x8000, pagesize 0x200, ivt offset 0x0
    Load image from 0x3a800 by ROM_API
    NOTICE:  BL31: v2.4(release):imx_5.10.35_2.0.0_imx8ulp_er-10-gf37e59b94
    NOTICE:  BL31: Built : 01:56:58, Jun 29 2021
    NOTICE:  upower_init: start uPower RAM service
    NOTICE:  user_upwr_rdy_callb: soc=b
    NOTICE:  user_upwr_rdy_callb: RAM version:12.6
    
    U-Boot 2021.07-rc4-00164-gb800e19a6b (Jun 29 2021 - 10:23:30 +0800)
    
    CPU:   Freescale i.MX8ULP rev1.0 at 744 MHz
    Reset cause: POR
    Boot mode: Single boot
    Model: FSL i.MX8ULP EVK
    DRAM:  2 GiB
    MMC:   FSL_SDHC: 0, FSL_SDHC: 2
    Loading Environment from MMC... ***
    Warning - bad CRC, using default environment
    
    In:    serial@293a0000
    Out:   serial@293a0000
    Err:   serial@293a0000
    Net:
    Warning: ethernet@29950000 (eth0) using random MAC address -
    96:35:88:62:e0:44
    eth0: ethernet@29950000
    Hit any key to stop autoboot:  0
    
    Signed-off-by: Peng Fan <peng.fan@nxp.com>