media: i2c: imx290: Add H and V flip controls

The sensor supports horizontal and vertical flips, so support them
through V4L2_CID_HFLIP and V4L2_CID_VFLIP.

This sensor does NOT change the Bayer order when changing the
direction of readout, therefore no special handling is required for
that.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>