IMX51 is already EOL and IMX53 is going to be EOL in Feb 2026.
https://www.nxp.com/products/nxp-product-information/nxp-product-programs/product-longevity:PRDCT_LONGEVITY_HM
Digi ConnectCore Wi-i.MX53
Genesi Efika MX
FreeBSD own DTSI for imx51 and imx53
Also remove the sys/modules/dtb/imx5 for i.MX53 quick start board, still active but not in stock. If someone wants to keep this its needs to be updated with the new paths that the device tree subdirectory uses.
https://www.nxp.com/design/design-center/development-boards-and-designs/i-mx-evaluation-and-development-boards/i-mx53-quick-start-board:IMX53QSB