ARM: configs: enable Marvell Armada 39x in multi_v7_defconfig

Following the introduction of the Marvell Armada 39x support, let's
enable this support by default in multi_v7_defconfig.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: <arm@kernel.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/configs/multi_v7_defconfig

@@ -16,6 +16,7 @@ CONFIG_ARCH_MVEBU=y
 CONFIG_MACH_ARMADA_370=y
 CONFIG_MACH_ARMADA_375=y
 CONFIG_MACH_ARMADA_38X=y
+CONFIG_MACH_ARMADA_39X=y
 CONFIG_MACH_ARMADA_XP=y
 CONFIG_MACH_DOVE=y
 CONFIG_ARCH_BCM=y