hardware/video.d: Allow read access to /dev/mtk_cmdq

Videos in UT 20.04 Morph browser for example among other apps (like TELEports) are entirely green on Volla Phone; similar issues were also seen on Xiaomi Redmi Note 8 Pro, so add the required nodes common between them here as it's likely other MediaTek SoC devices will also suffer from the same issue.

For reference all the Redmi Note 8 nodes: rubencarneiro/xiaomi-begonia@ae63cb15