media: smiapp: Query the V4L2 endpoint for a specific bus type

Instead of opportunistically trying to gather some information from the
V4L2 endpoint, set the bus type and let the V4L2 fwnode framework figure
out the configuration.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>