insmod will tell us when the module failed to load.  We do no further
processing on the return from i2c_add_driver(), so just return what
i2c_add_driver() did, instead of storing it.

Add __init/__exit annotations while we're at it.
Signed-off-by: NArthur Othieno <apgo@patchbomb.org>
Acked-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NPetr Vandrovec <petr@vandrovec.name>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>