media: i2c: imx290: Add support for 74.25MHz external clock

Backport from https://patchwork.linuxtv.org/project/linux-media/list/?series=9918



The sensor supports either a 37.125 or 74.25MHz external, but
the driver only supported 37.125MHz.

Add the relevant register configuration for either clock
frequency option.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>