defconfig: kona: Enable support for external viewer device

Enable USB Video Class (UVC) device support and media drivers for
USB bus for enabling video input devices, such as camera streamers
over USB.

Change-Id: I40b9bac228765e399f629875dc65b2f424346053
Signed-off-by: Sathish Ambley <sathishambley@codeaurora.org>