ARM: exynos_defconfig: Enable options to mount a rootfs via NFS

commit 19f79ccf6d77409cd138bce8db206cdac7fd5ea7 upstream.

This patch enables the options to mount a rootfs over NFS and also
support for automatic configuration of IP addresses during boot as
needed by NFS.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene@kernel.org>
Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>