[media] rtl28xxu: correct usb_clear_halt() usage

It is not allowed to call usb_clear_halt() after urbs are submitted.
That causes oops sometimes. Move whole streaming_ctrl() logic to
power_ctrl() in order to avoid wrong usb_clear_halt() use. Also,
configuring streaming endpoint in streaming_ctrl() sounds like a
little bit wrong as it is aimed for control stream gate.

Reported-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>