net: mv643xx_eth: remove deprecated inet_lro support

With recent support for GRO, there is no need to keep both LRO and
GRO. This patch therefore removes the deprecated inet_lro support
from mv643xx_eth. This is work is based on an experimental patch
provided by Eric Dumazet and Willy Tarreau.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Based-on-patch-by: Eric Dumazet <eric.dumazet@gmail.com>
Based-on-patch-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>