[media] Revert "[media] media: mx2_camera: Fix mbus format handling"

This reverts commit d509835e. That commit
breaks support for the generic pass-through mode in the driver for formats,
not natively supported by it. Besides due to a merge conflict it also breaks
driver compilation:

drivers/media/video/mx2_camera.c: In function 'mx2_camera_set_bus_param':
drivers/media/video/mx2_camera.c:937: error: 'pixfmt' undeclared (first use in this function)
drivers/media/video/mx2_camera.c:937: error: (Each undeclared identifier is reported only once
drivers/media/video/mx2_camera.c:937: error: for each function it appears in.)

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>