media: uvcvideo: Cleanup uvc_ctrl_add_info() error handling

There is only 1 error exit in uvc_ctrl_add_info(), so using goto style
error handling is not necessary. Also the kfree(ctrl->uvc_data) on error
is not necessary, because the only error exit is for the kzalloc() of
ctrl->uvc_data failing.

Remove all the error handling cruft and simply do "return -ENOMEM" on
kzalloc() failure.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>