[media] tw5864: add missing HAS_DMA dependency

Fix this warning:

warning: (VIDEO_TW5864 && VIDEO_MEDIATEK_VCODEC) selects VIDEOBUF2_DMA_CONTIG which has unmet direct dependencies (MEDIA_SUPPORT && HAS_DMA)

This driver depends on HAS_DMA.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>