dt-bindings: crypto: Drop obsolete mediatek,eip97-crypto

The mediatek,eip97-crypto binding is half abandoned. The driver was
dropped in 2020 as the Mediatek platforms use InsideSecure block and
the driver for it. All the platforms except MT7623 were updated. A
patch to update it was submitted, but never addressed the review
comments.

Link: https://lore.kernel.org/all/20210303080923.16761-1-vic.wu@mediatek.com/


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>