arm: Remove apx4devkit board

This board has not been converted to CONFIG_DM_MMC by the deadline of
v2019.04, which is almost two years ago.  In addition there are other DM
migrations it is also missing.  Remove it.

Cc: Lauri Hintsala <lauri.hintsala@bluegiga.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Acked-by: Lauri Hintsala <lauri.hintsala@silabs.com<mailto:lauri.hintsala@silabs.com>>
Signed-off-by: Tom Rini <trini@konsulko.com<mailto:trini@konsulko.com>>
8 files changed