boards: mimxrt1024_evk: enable mcux ethernet driver and pins

Enables the mcux ethernet driver and pin muxes on the
mimxrt1024_evk board in the same way as is done on the
mimxrt1020_evk and mimxrt1050_evk.

Documentation updated accordingly.

Signed-off-by: Mikkel Jakobsen <mikkel.aunsbjerg@prevas.dk>