net: calxedaxgmac: fix condition in xgmac_set_features()

The "changed" variable should be a 64 bit type, otherwise it can't store
all the features.  The way the code is now the test for whether
NETIF_F_RXCSUM changed is always false and we return immediately.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>