bridge: Allow tail-call on br_pass_frame_up

This patch allows tail-call on the call to br_pass_frame_up
in br_handle_frame_finish.  This is now possible because of the
previous patch to call br_pass_frame_up last.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>