media: uvcvideo: Set capability in s_param

Fixes v4l2-compliance:

Format ioctls (Input 0):
                warn: v4l2-test-formats.cpp(1339): S_PARM is supported but doesn't report V4L2_CAP_TIMEPERFRAME
                fail: v4l2-test-formats.cpp(1241): node->has_frmintervals && !cap->capability

Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>