media: ov5640: Restrict sizes to mbus code

The ov5640 driver supports different sizes for different mbus_codes.
In particular:

- 8bpp modes: high resolution sizes (>= 1280x720)
- 16bpp modes: all sizes
- 24bpp modes: low resolutions sizes (< 1280x720)

Restrict the frame sizes enumerations to the above constraints.

While at it, make sure the fse->mbus_code parameter is valid, and return
-EINVAL if it's not.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>