media: i2c: imx290: Support 60fps in 2 lane operation

Commit "97589ad6 media: i2c: imx290: Add support for 2 data lanes"
added support for running in two lane mode (instead of 4), but
without changing the link frequency that resulted in a max of 30fps.

Commit "98e0500e

 media: i2c: imx290: Add configurable link frequency
and pixel rate" then doubled the link frequency when in 2 lane mode,
but didn't undo the correction for running at only 30fps, just extending
horizontal blanking instead.

Remove the 30fps limit on 2 lane by correcting the register config
in accordance with the datasheet for 60fps operation over 2 lanes.

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