Add support for the RaspberryPi Camera v2 which is an IMX219 8MP module:
 - https://datasheets.raspberrypi.com/camera/camera-v2-schematics.pdf
 - has its own on-board 24MHz osc so no clock required from baseboard
 - pin 11 enables 1.8V and 2.8V LDO which is connected to
   GW74xx MIPI_GPIO4 (IMX8MP GPIO1_IO4) so we use this as a gpio

Support is added via a device-tree overlay.

The IMX219 supports RAW8/RAW10 image formats.

Example configuration:
media-ctl -l "'imx219 3-0010':0->'csis-32e40000.csi':0[1]"
media-ctl -v -V "'imx219 3-0010':0 [fmt:SRGGB8/640x480 field:none]"
media-ctl -v -V "'crossbar':0 [fmt:SRGGB8/640x480 field:none]"
media-ctl -v -V "'mxc_isi.0':0 [fmt:SRGGB8/640x480 field:none]"
v4l2-ctl --set-fmt-video=width=640,height=480,pixelformat=RGGB
v4l2-ctl --stream-mmap --stream-to=frame.raw --stream-count=1
convert -size 640x480 -depth 8 gray:frame.raw frame.png
gst-launch-1.0 v4l2src ! \
  video/x-bayer,format=rggb,width=640,height=480,framerate=10/1 ! \
  bayer2rgb ! fbdevsink
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>