[media] s5p-mfc: set capablity bus_info as required by VIDIOC_QUERYCAP

The driver doesn't set the struct v4l2_capability bus_info field so the
v4l2-compliance tool reports the following errors for VIDIOC_QUERYCAP:

Required ioctls:
                VIDIOC_QUERYCAP returned 0 (Success)
                fail: v4l2-compliance.cpp(304): string empty
                fail: v4l2-compliance.cpp(528): check_ustring(vcap.bus_info, sizeof(vcap.bus_info))
        test VIDIOC_QUERYCAP: FAIL

This patch fixes by setting the field in VIDIOC_QUERYCAP ioctl handler:

Required ioctls:
                VIDIOC_QUERYCAP returned 0 (Success)
        test VIDIOC_QUERYCAP: OK

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>