Add CONFIG_HAS_ETH0 to all boards with TSEC

The 85xx code now relies on CONFIG_HAS_ETH0 to determine whether
to update TSEC1's device-tree node, so we need to add it
to all the boards with TSECs.  Do this for 83xx and 86xx, too,
since they will eventually do something similar.

Signed-off-by: Andy Fleming <afleming@freescale.com>