board/ls2080a, ls1088a: Add check for mc-dpl applied in fdt

board/ls2080a, ls1088a: Add check for mc-dpl applied in fdt

Function fdt_fixup_board_enet() performs fdt fixup. Only return
fdt_status_okay() when both MC is applied and DPL is deployed, else
return fdt_status_fail().

This check is added to LS1088A/LS2080A/LS2088A boards.

Signed-off-by: Yogesh Gaur <yogeshnarayan.gaur@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>