Add support to enable/disable builtin GbE

In case we are going to use this in future designs.

BUG=none
TEST=none
BRANCH=none

Change-Id: I750addf10e4fe6f8240f8c8262253f8af7027e29
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/55844
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/3515
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2 files changed