configs/freescale_imx8m*: bump BSP components to 5.4.70_2.3.0

configs/freescale_imx8m*: bump BSP components to 5.4.70_2.3.0

Bump ATF, U-Boot and Linux kernel to the NXP BSP 5.4.70_2.3.0 versions.

Note for configs/freescale_imx8mmevk:

    On 5.4.70_2.3.0 the default "i.MX8MM LPDDR4 EVK RevB board" support is
    removed and replaced by "i.MX8MM LPDDR4 EVK with QCA WIFI revB board".

    In case an older revB board is used, then the following step in U-Boot is
    needed:

    => setenv fdt_file imx8mm-evk-revb-qca-wifi.dtb
    => saveenv
    => reset

Build- and run-tested on:
    o i.MX8MN DDR4 EVK
    o i.MX8MQ EVK
Build-tested only for other configs.

Signed-off-by: Stephane Viau <stephane.viau@oss.nxp.com>
Tested-by: Stephane Viau <stephane.viau@oss.nxp.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>