Integrate u-boot-seco-imx/seco_lf_v2021.04_develop_c72n_ym

Commit: https://git.seco.com/edgehog/bsp/nxp/u-boot-seco-imx/-/commit/cd2d549b1bd2b2a4c92299a802b622748b71f157

[C72n][SPL][DEFCONFIG] enable boot from eMMC

fix bug when trying to boot from eMMC:

mmc_load_image_raw_sector: mmc block read error SPL: failed to boot from all boot devices ### ERROR ### Please RESET the board ###

• delete raw sector correction (derived from evk, not valid on our board)
• enable mmc usage at SPL