i2c: Minor fixes to upgrading-clients document

* Typical legacy drivers implemented method .detach_client, not
  .detach_adapter.
* Drop all references to __devexit, as i2c drivers shouldn't use it.

Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
1 file changed