ARM: davinci: Orphan Spectrum Digital AM18xx EVM

ARM: davinci: Orphan Spectrum Digital AM18xx EVM

I had requested the da850 boards because their previous maintainer
had an invalid e-mail address.  I work at Logic PD who makes
the da850-evm kits, so I have access to various boards of theirs.

The Spectrum Digital AM18xx board is based on the Logic PD
da850 EVM, but it's not the same company.  Since I don't have the
hardware to test/verify changes, I would prefer to not be
responsible for this board.

Signed-off-by: Adam Ford <aford173@gmail.com>