[media] dvb_usb_v2: change USB stream config logic

Initial / default USB stream configuration is now set always as a
dvb_usb_device_properties. Dynamic configuration is done top of
that if callback .get_usb_stream_config() exists. Default values
are set when callback is called so callback needs only change
values that are different than default.

In addition of that define two macros DVB_USB_STREAM_BULK() and
DVB_USB_STREAM_ISOC() for filling struct usb_data_stream_properties

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>