gro: avoid checking for a failed search

After searching for a protocol handler in dev_gro_receive, checking for
failure is redundant. Skip the failure code after finding the
corresponding handler.

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Richard Gobert <richardbgobert@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20221108123320.GA59373@debian
Signed-off-by: Paolo Abeni <pabeni@redhat.com>