media: synopsys: add driver for the designware mipi csi-2 receiver

media: synopsys: add driver for the designware mipi csi-2 receiver

The Synopsys DesignWare MIPI CSI-2 Receiver is a CSI-2 bridge with
one input port and one output port. It receives the data with the
help of an external MIPI PHY (C-PHY or D-PHY) and passes it to e.g.,
the Rockchip Video Capture (VICAP) block on recent Rockchip SoCs.

Add a V4L2 subdevice driver for this unit.

Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Mehdi Djait <mehdi.djait@linux.intel.com>
Signed-off-by: Michael Riesch <michael.riesch@collabora.com>
[Sakari Ailus: Make sparse and smatch happy.]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>