net: netcp: use hw capability to remove FCS word from rx packets

Some of the newer Ethernet switch hw (such as that on k2e/l/g) can
strip the Etherenet FCS from packet at the port 0 egress of the switch.
So use this capability instead of doing it in software.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>