media: ipu3-imgu: VIDIOC_QUERYCAP: Fix bus_info

bus_info field had a different value for the media entity and the video
device.

Fixes v4l2-compliance:

v4l2-compliance.cpp(637): media bus_info 'PCI:0000:00:05.0' differs from
			  V4L2 bus_info 'PCI:viewfinder'

Reviewed-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>