media: i2c: Add support for the OV5648 image sensor

The OV5648 is a 5 Mpx CMOS image sensor, connected via MIPI CSI-2
in a one or two lane configuration.

Most of the features of the hardware are supported, including:
- Auto and manual exposition/gain
- Auto and manual white balance
- Horizontal and vertical flip
- Test patterns

But the following are still missing:
- Debanding, based on power source frequency;
- Exposition setting correlated to time units.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>