arm: mvebu: Update defconfig to select USB support

Cc: Lior Amsalem <alior@marvell.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Tested-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Tested-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>