media: imx-pxp: Don't set bus_info manually in .querycap()

The v4l2_capability.bus_info field is set by the V4L2 core when left
empty by the .querycap() handler. This is the recommended practice, in
order to ensure bus_info coherence between drivers. Don't set it
manually.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>