Documentation: Add DT bindings for video modules

Bring over DT bindings for MSM video modules from branch msm-4.14
'commit 195f5d0cdc2c ("cnss2: Do not handle MHI device
error during driver unloading")'.

CRs-Fixed: 2344373
Change-Id: Iff925d463e99db51d78514dbe2af3486d3213d6f
Signed-off-by: Vaibhav Deshu Venkatesh <vdeshuve@codeaurora.org>