i2c: octeon: Rename driver to prepare for split

This is an intermediate commit in preparation of the driver split.
The module rename in this commit will be reverted in the next patch,
this is just done to make the series bisectible.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>