Define tsec flag values in config files

The tsec_info structure and array has a "flags" field for each
ethernet controller.  This field is the only reason there are
settings.  Switch to defining TSECn_FLAGS for each controller
in the config header, and we can greatly simplify the array, and
also simplify the addition of future boards.

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