powerpc/85xx: enable E1000 NIC to mpc85xx_defconfig

E1000 NIC is a common used Ethernet card. Enable it as default
for mpc85xx platform.

other change is due to make savedefconfig

Reported-by: Fu Jiwei <b36666@freescale.com>
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>