Controls are applied to the hardware in the configure operation of the
VSP entities, which is only called when starting the video stream. To
enable runtime modification of controls we need to call the configure
operations for every frame. Doing so is currently not safe, as most
parameters shouldn't be modified during streaming. Furthermore the
configure operation can sleep, preventing it from being called from the
frame completion interrupt handler for the next frame.

Fix this by adding an argument to the configure operation to tell
entities whether to perform a full configuration (as done now) or a
partial runtime configuration. In the latter case the operation will
only configure the subset of parameters related to runtime-configurable
controls, and won't be allowed to sleep when doing so.

Because partial reconfiguration can depend on parameters computed when
performing a full configuration, the core guarantees that the configure
operation will always be called with full and partial modes in that
order at stream start. Entities thus don't have to duplicate
configuration steps in the full and partial code paths.

This change affects the VSP driver core only, all entities return
immediately from the configure operation when called for a partial
runtime configuration. Entities will be modified one by one in further
commits.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>