Metaknight: Remove legacy board
Metaknight: Remove legacy board

Metaknight has progressed past the point where the legacy board is
needed, and it's down to less than 100 bytes of free flash at this
point.

BRANCH=None
BUG=None
TEST=make -j buildall

Signed-off-by: Diana Z <cb2016afc7183e5356c690dc63b4ba817470501a@chromium.org>
Change-Id: Ie8899bc294745dceddc207428e8f5e8f8222da13
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2964921
Reviewed-by: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec