drivers: media: rp1_cfe: Fix link validate test for pixel format

Now that we have removed unique PISP media bus codes, the cfe format
table has multiple entries with the same media bus code for 16-bit
formats. The test in cfe_video_link_validate() did not account for this.
Fix it by testing the media bus code and the V4L2 pixelformat 4cc
together.

As a drive-by, ensure we have a valid CSI2 datatype id when programming
the hardware block.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>