ARM: exynos_defconfig: Enable NFSv4 client

commit 1c1fb9b0c89a2506e556114c813a606bc1508d49 upstream.

NFS client is already enabled (NFS_FS) and by default it enables clients
for version 2 and 3. Enable explicitly the version 4 client to utilize
the newer protocol.

The NFS client is especially useful for testing kernel in automated
environments (network boot with network file system).

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
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>