defconfig: enable drm/kms driver in mediabox config

Enable drm/kms driver in msmcortex media config.
Enable VT in msmcortex media config.

CRs-Fixed: 2002381
Change-Id: I57a7a737d1f0bc22f229c087a6932b9e73c0537c
Signed-off-by: Manoj Kumar AVM <manojavm@codeaurora.org>
Signed-off-by: Ray Zhang <rayz@codeaurora.org>