pch_gbe: memory corruption calling pch_gbe_validate_option()

pch_gbe_validate_option() modifies 32 bits of memory but we pass
&hw->phy.autoneg_advertised which only has 16 bits and &hw->mac.fc
which only has 8 bits.

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