dt-bindings: ata: atmel: remove at91 compact flash documentation

The compatible "at91rm9200-cf" is not used by any driver, hence remove the
corresponding documentation.

Signed-off-by: Hari Prasath Gujulan Elango <[email protected]>
Acked-by: Rob Herring <[email protected]>
Acked-by: Nicolas Ferre <[email protected]>
[cassel: add missing space in commit log]
Signed-off-by: Niklas Cassel <[email protected]>

Author: gehariprasath