efficeon-agp leaks 'struct agp_bridge_data' in error paths of agp_efficeon_probe()

(This is a resend of a patch originally submitted on 24-Jul-2007 00:14)

Ok, this is something the coverity checker found (CID: 1813).
I'm not at all intimate with this code, so I'm not sure if this
attempt at a fix is correct (but at least it compiles).

Please look it over and NACK if bad or merge if good ;-)

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>