Revert "staging: octeon: delete driver"

This reverts commit 710d7fbe.
Re-instate the code so subsequent commits can clean it up and get it
building properly.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20200205001116.14096-3-chris.packham@alliedtelesis.co.nz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>