media: iris: implement vb2 streaming ops

During the stream on operation, send HFI_CMD_START on the capture and
output planes to start processing on the respective planes.

During the stream off operation, send HFI_CMD_STOP to the firmware,
which is a synchronous command. After the response is received by the
firmware, the session is closed on the firmware.

Introduce different states for the instance and state transitions.

IRIS_INST_INIT - video instance is opened.
IRIS_INST_INPUT_STREAMING - stream on is completed on output plane.
IRIS_INST_OUTPUT_STREAMING - stream on is completed on capture plane.
IRIS_INST_STREAMING - stream on is completed on both output and capture
planes.
IRIS_INST_DEINIT - video instance is closed.
IRIS_INST_ERROR - error state.

                   |
                   v
            -------------
  +---------|   INIT    |---------  +
  |         -------------           |
  |            ^    ^               |
  |           /      \              |
  |          /        \             |
  |         v          v            |
  |    -----------    -----------   |
  |   |   INPUT         OUTPUT  |   |
  |---| STREAMING     STREAMING |---|
  |    -----------    -----------   |
  |        ^            ^           |
  |         \          /            |
  |          \        /             |
  |           v      v              |
  |         -------------           |
  |--------|  STREAMING |-----------|
  |         -------------           |
  |               |                 |
  |               |                 |
  |               v                 |
  |          -----------            |
  +-------->|  DEINIT   |<----------+
  |          -----------            |
  |               |                 |
  |               |                 |
  |               v                 |
  |          ----------             |
  +-------->|   ERROR  |<-----------+
             ----------.

Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
Tested-by: Stefan Schmidt <stefan.schmidt@linaro.org> # x1e80100 (Dell XPS 13 9345)
Reviewed-by: Stefan Schmidt <stefan.schmidt@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-HDK
Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>