gve: fix unmatched u64_stats_update_end()

The u64_stats_update_end() call is supposed to be inside the curly
braces so it pairs with the u64_stats_update_begin().

Fixes: 37149e93

 ("gve: Implement packet continuation for RX.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>