media: sun6i: Add A64 CSI block support

CSI block in Allwinner A64 has similar features as like in H3,
but the default CSI_SCLK rate cannot work properly to drive the
connected sensor interface.

The tested mod cock rate is 300 MHz and BSP vfe media driver is also
using the same rate. Unfortunately there is no valid information about
clock rate in manual or any other sources except the BSP driver. so more
faith on BSP code, because same has tested in mainline.

So, add support for A64 CSI block by setting updated mod clock rate.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>