ARM: exynos_defconfig: Enable rtl8152 ethernet driver for Odroid-XU4

Odroid-XU4 has a RTL8153-CG gigabit Ethernet adapter, connected over
USB 3.0.

Signed-off-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>