drivers: Drop GbE stub drivers

These NIC stub drivers were to initialize the Gigabit Ethernet adapters
just enough to keep coreboot from trying to execute an option ROM.
However this is no longer required as non-VGA option roms are not ran;
See:

b32816e Remove PCI_ROM_RUN option

Change-Id: Idc44619767c631c5fcf550a5948c8947bde5e218
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5777
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martin.roth@se-eng.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
mainboard/ibase/mb899: Indent devicetree.cb

Change-Id: I29037c322dac5ed9ebc36b95bc1981acf21e5bd0
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5778
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martin.roth@se-eng.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>